From 51a114a3487f9af6c242e94dbabddf1b92f2f169 Mon Sep 17 00:00:00 2001
From: Erik Krogh Kristensen <erik-krogh@github.com>
Date: Wed, 20 Jan 2021 16:12:37 +0100
Subject: [PATCH 1/6] update es externs

---
 javascript/externs/es/es3.js             | 472 +++++++++-------
 javascript/externs/es/es5.js             |  53 +-
 javascript/externs/es/es6.js             | 673 ++++++++++++++++++++---
 javascript/externs/es/es6_collections.js |  59 +-
 javascript/externs/es/intl.js            | 104 +++-
 5 files changed, 1038 insertions(+), 323 deletions(-)

diff --git a/javascript/externs/es/es3.js b/javascript/externs/es/es3.js
index 43968041b754..57efb4984af0 100644
--- a/javascript/externs/es/es3.js
+++ b/javascript/externs/es/es3.js
@@ -27,26 +27,34 @@
 
 // START ES6 RETROFIT CODE
 // symbol, Symbol and Symbol.iterator are actually ES6 types but some
-// Some types require them to be part of their definition (such as Array).
+// base types require them to be part of their definition (such as Array).
 
 
-// TODO(johnlenz): symbol should be a primitive type.
-/** @typedef {?} */
-var symbol;
-
 /**
- * @param {string=} opt_description
+ * @constructor
+ * @param {*=} opt_description
  * @return {symbol}
+ * @nosideeffects
+ * Note: calling `new Symbol('x');` will always throw, but we mark this
+ * nosideeffects because the compiler does not promise to preserve all coding
+ * errors.
  */
 function Symbol(opt_description) {}
 
 
+/**
+ * @const {string|undefined}
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/description
+ */
+Symbol.prototype.description;
+
+
 /**
  * @param {string} sym
- * @return {symbol|undefined}
+ * @return {symbol}
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/for
  */
-Symbol.for;
+Symbol.for = function(sym) {};
 
 
 /**
@@ -54,18 +62,87 @@ Symbol.for;
  * @return {string|undefined}
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/keyFor
  */
-Symbol.keyFor;
+Symbol.keyFor = function(sym) {};
 
 
 // Well known symbols
 
-/** @const {symbol} */
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/asyncIterator
+ * @const {symbol}
+ */
+Symbol.asyncIterator;
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/hasInstance
+ * @const {symbol}
+ */
+Symbol.hasInstance;
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/isConcatSpreadable
+ * @const {symbol}
+ */
+Symbol.isConcatSpreadable;
+
+/**
+ * @const {symbol}
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/iterator
+ */
 Symbol.iterator;
 
-/** @const {symbol} */
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/match
+ * @const {symbol}
+ */
+Symbol.match;
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/matchAll
+ * @const {symbol}
+ */
+Symbol.matchAll;
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/replace
+ * @const {symbol}
+ */
+Symbol.replace;
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/search
+ * @const {symbol}
+ */
+Symbol.search;
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/species
+ * @const {symbol}
+ */
+Symbol.species;
+
+// /**
+//  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/split
+//  * @const {symbol}
+//  */
+// Symbol.split;
+
+/**
+ * @const {symbol}
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/toPrimitive
+ */
+Symbol.toPrimitive;
+
+/**
+ * @const {symbol}
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/toStringTag
+ */
 Symbol.toStringTag;
 
-/** @const {symbol} */
+/**
+ * @const {symbol}
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/unscopables
+ */
 Symbol.unscopables;
 
 
@@ -89,9 +166,10 @@ IIterableResult.prototype.value;
  */
 function Iterable() {}
 
-// TODO(johnlenz): remove this when the compiler understands "symbol" natively
+// TODO(johnlenz): remove the suppression when the compiler understands
+// "symbol" natively
 /**
- * @return {Iterator<VALUE>}
+ * @return {!Iterator<VALUE, ?, *>}
  * @suppress {externsValidation}
  */
 Iterable.prototype[Symbol.iterator] = function() {};
@@ -99,23 +177,26 @@ Iterable.prototype[Symbol.iterator] = function() {};
 
 
 /**
+ * TODO(b/142881197): UNUSED_RETURN_T and UNUSED_NEXT_T are not yet used for
+ * anything. https://github.com/google/closure-compiler/issues/3489
  * @interface
- * @template VALUE
+ * @template VALUE, UNUSED_RETURN_T, UNUSED_NEXT_T
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/The_Iterator_protocol
  */
 function Iterator() {}
 
 /**
- * @param {VALUE=} value
+ * @param {?=} opt_value
  * @return {!IIterableResult<VALUE>}
  */
-Iterator.prototype.next;
+Iterator.prototype.next = function(opt_value) {};
 
 
 /**
  * Use this to indicate a type is both an Iterator and an Iterable.
+ *
  * @interface
- * @extends {Iterator<T>}
+ * @extends {Iterator<T, ?, *>}
  * @extends {Iterable<T>}
  * @template T
  */
@@ -126,7 +207,7 @@ function IteratorIterable() {}
 
 /**
  * @interface
- * @template KEY1, VALUE1
+ * @template IOBJECT_KEY, IOBJECT_VALUE
  */
 function IObject() {}
 
@@ -142,8 +223,8 @@ IArrayLike.prototype.length;
 
 /**
  * @constructor
- * @implements {IArrayLike<T>}
- * @template T
+ * @implements {IArrayLike<?>}
+ * @implements {Iterable<?>}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions_and_function_scope/arguments
  */
 function Arguments() {}
@@ -170,10 +251,12 @@ Arguments.prototype.caller;
 Arguments.prototype.length;
 
 /**
- * Not actually a global variable, but we need it in order for the current type
- * checker to typecheck the "arguments" variable in a function correctly.
- * TODO(tbreisacher): When the old type checker is gone, delete this and add
- * an 'arguments' variable of type Array<string> in the d8 externs.
+ * Not actually a global variable, when running in a browser environment. But
+ * we need it in order for the type checker to typecheck the "arguments"
+ * variable in a function correctly.
+ *
+ * TODO(tbreisacher): There should be a separate 'arguments' variable of type
+ * `Array<string>`, in the d8 externs.
  *
  * @type {!Arguments}
  * @see http://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Functions_and_function_scope/arguments
@@ -204,7 +287,7 @@ var undefined;
 /**
  * @param {string} uri
  * @return {string}
- * @nosideeffects
+ * @throws {URIError} when used wrongly.
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/decodeURI
  */
 function decodeURI(uri) {}
@@ -212,7 +295,7 @@ function decodeURI(uri) {}
 /**
  * @param {string} uri
  * @return {string}
- * @nosideeffects
+ * @throws {URIError} when used wrongly.
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/decodeURIComponent
  */
 function decodeURIComponent(uri) {}
@@ -220,7 +303,8 @@ function decodeURIComponent(uri) {}
 /**
  * @param {string} uri
  * @return {string}
- * @nosideeffects
+ * @throws {URIError} if one attempts to encode a surrogate which is not part of
+ * a high-low pair.
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/encodeURI
  */
 function encodeURI(uri) {}
@@ -228,7 +312,8 @@ function encodeURI(uri) {}
 /**
  * @param {string} uri
  * @return {string}
- * @nosideeffects
+ * @throws {URIError} if one attempts to encode a surrogate which is not part of
+ * a high-low pair.
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/encodeURIComponent
  */
 function encodeURIComponent(uri) {}
@@ -278,9 +363,9 @@ function isNaN(num) {}
 function parseFloat(num) {}
 
 /**
- * Parse an integer. Use of {@code parseInt} without {@code base} is strictly
+ * Parse an integer. Use of `parseInt` without `base` is strictly
  * banned in Google. If you really want to parse octal or hex based on the
- * leader, then pass {@code undefined} as the base.
+ * leader, then pass `undefined` as the base.
  *
  * @param {*} num
  * @param {number|undefined} base
@@ -290,8 +375,23 @@ function parseFloat(num) {}
  */
 function parseInt(num, base) {}
 
+
 /**
- * @param {string} code
+ * Represents a string of JavaScript code that is known to have come from a
+ * trusted source. Part of Trusted Types.
+ *
+ * The main body Trusted Types type definitions reside in the  file
+ * `w3c_trusted_types.js`. This definition was placed here so that it would be
+ * accessible to `eval()`.
+ *
+ * @constructor
+ * @see https://w3c.github.io/webappsec-trusted-types/dist/spec/#trusted-script
+ */
+function TrustedScript() {}
+
+
+/**
+ * @param {string|!TrustedScript} code
  * @return {*}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/eval
  */
@@ -325,6 +425,7 @@ Object.prototype.constructor = function() {};
  * @modifies {this}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineGetter
  * @return {undefined}
+ * @deprecated
  */
 Object.prototype.__defineGetter__ = function(sprop, fun) {};
 
@@ -338,6 +439,7 @@ Object.prototype.__defineGetter__ = function(sprop, fun) {};
  * @modifies {this}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineSetter
  * @return {undefined}
+ * @deprecated
  */
 Object.prototype.__defineSetter__ = function(sprop, fun) {};
 
@@ -369,6 +471,7 @@ Object.prototype.isPrototypeOf = function(other) {};
  * getter should be returned
  * @return {Function}
  * @nosideeffects
+ * @deprecated
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/lookupGetter
  */
 Object.prototype.__lookupGetter__ = function(sprop) {};
@@ -381,6 +484,7 @@ Object.prototype.__lookupGetter__ = function(sprop) {};
  *     setter should be returned.
  * @return {Function}
  * @nosideeffects
+ * @deprecated
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/lookupSetter
  */
 Object.prototype.__lookupSetter__ = function(sprop) {};
@@ -391,6 +495,7 @@ Object.prototype.__lookupSetter__ = function(sprop) {};
  *
  * @param {Function} fun
  * @return {*}
+ * @deprecated
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/noSuchMethod
  */
 Object.prototype.__noSuchMethod__ = function(fun) {};
@@ -421,7 +526,7 @@ Object.prototype.__proto__;
  * for..in loop, with the exception of properties inherited through the
  * prototype chain.
  *
- * @param {string} propertyName
+ * @param {string|symbol} propertyName
  * @return {boolean}
  * @nosideeffects
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/propertyIsEnumerable
@@ -455,33 +560,13 @@ Object.prototype.toSource = function() {};
 Object.prototype.toString = function() {};
 
 /**
- * Removes a watchpoint set with the {@see Object.prototype.watch} method.
- * Mozilla-only.
- * @param {string} prop The name of a property of the object.
- * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/unwatch
- * @return {undefined}
- */
-Object.prototype.unwatch = function(prop) {};
-
-/**
- * Returns the object's {@code this} value.
+ * Returns the object's `this` value.
  * @return {*}
  * @nosideeffects
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/valueOf
  */
 Object.prototype.valueOf = function() {};
 
-/**
- * Sets a watchpoint method.
- * Mozilla-only.
- * @param {string} prop The name of a property of the object.
- * @param {Function} handler A function to call.
- * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/watch
- * @return {undefined}
- */
-Object.prototype.watch = function(prop, handler) {};
-
-
 /**
  * @constructor
  * @param {...*} var_args
@@ -554,7 +639,7 @@ Function.prototype.toString = function() {};
  * @implements {IArrayLike<T>}
  * @implements {Iterable<T>}
  * @param {...*} var_args
- * @return {!Array<?>}
+ * @return {!Array}
  * @nosideeffects
  * @template T
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array
@@ -605,11 +690,12 @@ Array.prototype.join = function(opt_separator) {};
  */
 Array.prototype.pop = function() {};
 
+// TODO(bradfordcsmith): remove "undefined" from the var_args of push
 /**
  * Mutates an array by appending the given elements and returning the new
  * length of the array.
  *
- * @param {...T} var_args
+ * @param {...(T|undefined)} var_args
  * @return {number} The new length of the array.
  * @this {IArrayLike<T>}
  * @template T
@@ -645,9 +731,8 @@ Array.prototype.shift = function() {};
 /**
  * Extracts a section of an array and returns a new array.
  *
- * @param {*=} opt_begin Zero-based index at which to begin extraction.  A
- *     non-number type will be auto-cast by the browser to a number.
- * @param {*=} opt_end Zero-based index at which to end extraction.  slice
+ * @param {?number=} begin Zero-based index at which to begin extraction.
+ * @param {?number=} end Zero-based index at which to end extraction.  slice
  *     extracts up to but not including end.
  * @return {!Array<T>}
  * @this {IArrayLike<T>|string}
@@ -655,12 +740,12 @@ Array.prototype.shift = function() {};
  * @nosideeffects
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/slice
  */
-Array.prototype.slice = function(opt_begin, opt_end) {};
+Array.prototype.slice = function(begin, end) {};
 
 /**
  * Sorts the elements of an array in place.
  *
- * @param {function(T,T):number=} opt_compareFunction Specifies a function that
+ * @param {function(T,T):number=} opt_compareFn Specifies a function that
  *     defines the sort order.
  * @this {IArrayLike<T>}
  * @template T
@@ -668,17 +753,16 @@ Array.prototype.slice = function(opt_begin, opt_end) {};
  * @return {!Array<T>}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort
  */
-Array.prototype.sort = function(opt_compareFunction) {};
+Array.prototype.sort = function(opt_compareFn) {};
 
 /**
  * Changes the content of an array, adding new elements while removing old
  * elements.
  *
- * @param {*=} opt_index Index at which to start changing the array. If negative,
- *     will begin that many elements from the end.  A non-number type will be
- *     auto-cast by the browser to a number.
- * @param {*=} opt_howMany An integer indicating the number of old array elements
- *     to remove.
+ * @param {?number=} index Index at which to start changing the array. If
+ *     negative, will begin that many elements from the end.
+ * @param {?number=} howMany An integer indicating the number of old array
+ *     elements to remove.
  * @param {...T} var_args
  * @return {!Array<T>}
  * @this {IArrayLike<T>}
@@ -686,7 +770,7 @@ Array.prototype.sort = function(opt_compareFunction) {};
  * @template T
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/splice
  */
-Array.prototype.splice = function(opt_index, opt_howMany, var_args) {};
+Array.prototype.splice = function(index, howMany, var_args) {};
 
 /**
  * @return {string}
@@ -839,75 +923,6 @@ Array.prototype.input;
  */
 Array.prototype.length;
 
-/**
- * @param {IArrayLike<T>} arr
- * @param {?function(this:S, T, number, ?) : ?} callback
- * @param {S=} opt_context
- * @return {boolean}
- * @template T,S
- */
-Array.every = function(arr, callback, opt_context) {};
-
-/**
- * @param {IArrayLike<T>} arr
- * @param {?function(this:S, T, number, ?) : ?} callback
- * @param {S=} opt_context
- * @return {!Array<T>}
- * @template T,S
- */
-Array.filter = function(arr, callback, opt_context) {};
-
-/**
- * @param {IArrayLike<T>} arr
- * @param {?function(this:S, T, number, ?) : ?} callback
- * @param {S=} opt_context
- * @template T,S
- * @return {undefined}
- */
-Array.forEach = function(arr, callback, opt_context) {};
-
-/**
- * Mozilla 1.6+ only.
- * @param {IArrayLike<T>} arr
- * @param {T} obj
- * @param {number=} opt_fromIndex
- * @return {number}
- * @template T
- * @nosideeffects
- * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/indexOf
- */
-Array.indexOf = function(arr, obj, opt_fromIndex) {};
-
-/**
- * Mozilla 1.6+ only.
- * @param {IArrayLike<T>} arr
- * @param {T} obj
- * @param {number=} opt_fromIndex
- * @return {number}
- * @template T
- * @nosideeffects
- * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/lastIndexOf
- */
-Array.lastIndexOf = function(arr, obj, opt_fromIndex) {};
-
-/**
- * @param {IArrayLike<T>} arr
- * @param {?function(this:S, T, number, !Array<T>): R} callback
- * @param {S=} opt_context
- * @return {!Array<R>}
- * @template T,S,R
- */
-Array.map = function(arr, callback, opt_context) {};
-
-/**
- * @param {IArrayLike<T>} arr
- * @param {?function(this:S, T, number, ?) : ?} callback
- * @param {S=} opt_context
- * @return {boolean}
- * @template T,S
- */
-Array.some = function(arr, callback, opt_context) {};
-
 /**
  * Introduced in 1.8.5.
  * @param {*} arr
@@ -999,35 +1014,97 @@ Number.prototype.toString = function(opt_radix) {};
 
 // Properties.
 /**
- * @type {number}
+ * @const {number}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/MAX_VALUE
  */
 Number.MAX_VALUE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/MIN_VALUE
  */
 Number.MIN_VALUE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/NaN
  */
 Number.NaN;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/NEGATIVE_INFINITY
  */
 Number.NEGATIVE_INFINITY;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/POSITIVE_INFINITY
  */
 Number.POSITIVE_INFINITY;
 
+/**
+ * @constructor
+ * @param {number|string|bigint} arg
+ * @return {bigint}
+ * @nosideeffects
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt
+ */
+function BigInt(arg) {}
+
+/**
+ * Wraps a BigInt value to a signed integer between -2^(width-1) and
+ * 2^(width-1)-1.
+ * @param {number} width
+ * @param {bigint} bigint
+ * @return {bigint}
+ * @nosideeffects
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt/asIntN
+ */
+BigInt.asIntN = function(width, bigint) {};
+
+/**
+ * Wraps a BigInt value to an unsigned integer between 0 and (2^width)-1.
+ * @param {number} width
+ * @param {bigint} bigint
+ * @return {bigint}
+ * @nosideeffects
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt/asUintN
+ */
+BigInt.asUintN = function(width, bigint) {};
+
+/**
+ * Returns a string with a language-sensitive representation of this BigInt.
+ * @param {string|!Array<string>=} locales
+ * @param {Object=} options
+ * @return {string}
+ * @nosideeffects
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt/toLocaleString
+ * @override
+ */
+BigInt.prototype.toLocaleString = function(locales, options) {};
+
+/**
+ * Returns a string representing the specified BigInt object. The trailing "n"
+ * is not part of the string.
+ * @this {BigInt|bigint}
+ * @param {number=} radix
+ * @return {string}
+ * @nosideeffects
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt/toString
+ * @override
+ */
+BigInt.prototype.toString = function(radix) {};
+
+/**
+ * Returns the wrapped primitive value of a BigInt object.
+ * @return {bigint}
+ * @nosideeffects
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt/valueOf
+ * @override
+ */
+BigInt.prototype.valueOf = function() {};
+
 
 /**
  * @const
@@ -1190,49 +1267,49 @@ Math.toSource = function() {};
 // Properties:
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/E
  */
 Math.E;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/LN2
  */
 Math.LN2;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/LN10
  */
 Math.LN10;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/LOG2E
  */
 Math.LOG2E;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/LOG10E
  */
 Math.LOG10E;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/PI
  */
 Math.PI;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/SQRT1_2
  */
 Math.SQRT1_2;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/SQRT2
  */
 Math.SQRT2;
@@ -1696,6 +1773,7 @@ Date.prototype.valueOf;
 
 /**
  * @constructor
+ * @implements {Iterable<string>}
  * @param {*=} opt_str
  * @return {string}
  * @nosideeffects
@@ -1891,24 +1969,23 @@ String.prototype.quote = function() {};
  * This may have side-effects if the replacement function has side-effects.
  *
  * @this {String|string}
- * @param {RegExp|string} regex
- * @param {string|Function} str
- * @param {string=} opt_flags
+ * @param {RegExp|string} pattern
+ * @param {?string|function(string, ...?):*} replacement
  * @return {string}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace
  */
-String.prototype.replace = function(regex, str, opt_flags) {};
+String.prototype.replace = function(pattern, replacement) {};
 
 /**
  * Executes the search for a match between a regular expression and this String
  * object.
  *
  * @this {String|string}
- * @param {RegExp|string} regexp
+ * @param {RegExp|string} pattern
  * @return {number}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/search
  */
-String.prototype.search = function(regexp) {};
+String.prototype.search = function(pattern) {};
 
 /**
  * @this {String|string}
@@ -1983,19 +2060,21 @@ String.prototype.sup = function() {};
 
 /**
  * @this {String|string}
+ * @param {(string|Array<string>)=} opt_locales
  * @return {string}
  * @nosideeffects
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/toLocaleUpperCase
  */
-String.prototype.toLocaleUpperCase = function() {};
+String.prototype.toLocaleUpperCase = function(opt_locales) {};
 
 /**
  * @this {String|string}
+ * @param {(string|Array<string>)=} opt_locales
  * @return {string}
  * @nosideeffects
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/toLocaleLowerCase
  */
-String.prototype.toLocaleLowerCase = function() {};
+String.prototype.toLocaleLowerCase = function(opt_locales) {};
 
 /**
  * @this {String|string}
@@ -2047,7 +2126,7 @@ String.prototype.length;
  * @param {*=} opt_pattern
  * @param {*=} opt_flags
  * @return {!RegExp}
- * @nosideeffects
+ * @throws {SyntaxError} if opt_pattern is an invalid pattern.
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp
  */
 function RegExp(opt_pattern, opt_flags) {}
@@ -2065,9 +2144,7 @@ RegExp.prototype.compile = function(pattern, opt_flags) {};
 
 /**
  * @param {*} str The string to search.
- * @return {Array<string>} This should really return an Array with a few
- *     special properties, but we do not have a good way to model this in
- *     our type system. Also see String.prototype.match.
+ * @return {?RegExpResult}
  * @see http://msdn.microsoft.com/en-us/library/z908hy33(VS.85).aspx
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/exec
  */
@@ -2088,6 +2165,34 @@ RegExp.prototype.test = function(str) {};
  */
 RegExp.prototype.toString = function() {};
 
+/**
+ * @constructor
+ * @extends {Array<string>}
+ */
+var RegExpResult = function() {};
+
+
+/** @type {number} */
+RegExpResult.prototype.index;
+
+
+/** @type {string} */
+RegExpResult.prototype.input;
+
+
+/** @type {number} */
+RegExpResult.prototype.length;
+
+
+/**
+ * Not actually part of ES3; was added in 2018.
+ * https://github.com/tc39/proposal-regexp-named-groups
+ *
+ * @type {!Object<string, string>}
+ */
+RegExpResult.prototype.groups;
+
+
 // Constructor properties:
 
 /**
@@ -2195,6 +2300,13 @@ RegExp.prototype.ignoreCase;
  */
 RegExp.prototype.lastIndex;
 
+/**
+ * Whether or not the regular expression uses lastIndex.
+ * @type {boolean}
+ * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/sticky
+ */
+RegExp.prototype.sticky;
+
 /**
  * Whether or not to search in strings across multiple lines.
  * @type {boolean}
@@ -2209,6 +2321,12 @@ RegExp.prototype.multiline;
  */
 RegExp.prototype.source;
 
+/**
+ * The flags the regex was created with.
+ * @type {string}
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/flags
+ */
+RegExp.prototype.flags;
 
 /**
  * @constructor
@@ -2359,40 +2477,12 @@ function TypeError(opt_message, opt_file, opt_line) {}
  */
 function URIError(opt_message, opt_file, opt_line) {}
 
-
 // JScript extensions.
 // @see http://msdn.microsoft.com/en-us/library/894hfyb4(VS.80).aspx
 
 /**
  * @see http://msdn.microsoft.com/en-us/library/7sw4ddf8.aspx
  * @type {function(new:?, string, string=)}
+ * @deprecated
  */
 function ActiveXObject(progId, opt_location) {}
-
-/**
- * @return {string}
- * @nosideeffects
- * @see http://msdn.microsoft.com/en-us/library/9k34bww2(VS.80).aspx
- */
-function ScriptEngine() {}
-
-/**
- * @return {number}
- * @nosideeffects
- * @see http://msdn.microsoft.com/en-us/library/yf25ky07(VS.80).aspx
- */
-function ScriptEngineMajorVersion() {}
-
-/**
- * @return {number}
- * @nosideeffects
- * @see http://msdn.microsoft.com/en-us/library/wx3812cz(VS.80).aspx
- */
-function ScriptEngineMinorVersion() {}
-
-/**
- * @return {number}
- * @nosideeffects
- * @see http://msdn.microsoft.com/en-us/library/e98hsk2f(VS.80).aspx
- */
-function ScriptEngineBuildVersion() {}
diff --git a/javascript/externs/es/es5.js b/javascript/externs/es/es5.js
index ffbc01e6aba8..05d00439fae4 100644
--- a/javascript/externs/es/es5.js
+++ b/javascript/externs/es/es5.js
@@ -22,9 +22,9 @@
 
 
 /**
- * @param {Object|undefined} selfObj Specifies the object to which |this| should
- *     point when the function is run. If the value is null or undefined, it
- *     will default to the global object.
+ * @param {?Object|undefined} selfObj Specifies the object to which |this|
+ *     should point when the function is run. If the value is null or undefined,
+ *     it will default to the global object.
  * @param {...*} var_args Additional arguments that are partially
  *     applied to fn.
  * @return {!Function} A partially-applied form of the Function on which
@@ -66,13 +66,12 @@ String.prototype.trimRight = function() {};
  * A object property descriptor used by Object.create, Object.defineProperty,
  * Object.defineProperties, Object.getOwnPropertyDescriptor.
  *
- * Note: not a real constructor.
- * @constructor
+ * @record
  * @template THIS
  */
 function ObjectPropertyDescriptor() {}
 
-/** @type {*} */
+/** @type {(*|undefined)} */
 ObjectPropertyDescriptor.prototype.value;
 
 /** @type {(function(this: THIS):?)|undefined} */
@@ -92,29 +91,33 @@ ObjectPropertyDescriptor.prototype.configurable;
 
 
 /**
- * @param {Object} proto
- * @param {Object=} opt_properties  A map of ObjectPropertyDescriptors.
+ * @param {?Object} proto
+ * @param {?Object<string|symbol, !ObjectPropertyDescriptor<?>>=} properties
+ *     A map of ObjectPropertyDescriptors.
  * @return {!Object}
  * @nosideeffects
  * @see https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Object/create
  */
-Object.create = function(proto, opt_properties) {};
+Object.create = function(proto, properties) {};
 
 
 /**
- * @param {!Object} obj
- * @param {string} prop
- * @param {!Object} descriptor A ObjectPropertyDescriptor.
- * @return {!Object}
+ * @template T
+ * @param {T} obj
+ * @param {string|symbol} prop
+ * @param {!ObjectPropertyDescriptor<T>} descriptor A ObjectPropertyDescriptor.
+ * @return {T}
  * @see https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Object/defineProperty
  */
 Object.defineProperty = function(obj, prop, descriptor) {};
 
 
 /**
- * @param {!Object} obj
- * @param {!Object} props A map of ObjectPropertyDescriptors.
- * @return {!Object}
+ * @template T
+ * @param {T} obj
+ * @param {!Object<string|symbol, !ObjectPropertyDescriptor<T>>} props A map of
+ *     ObjectPropertyDescriptors.
+ * @return {T}
  * @see https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Object/defineProperties
  */
 Object.defineProperties = function(obj, props) {};
@@ -122,7 +125,7 @@ Object.defineProperties = function(obj, props) {};
 
 /**
  * @param {T} obj
- * @param {string} prop
+ * @param {string|symbol} prop
  * @return {!ObjectPropertyDescriptor<T>|undefined}
  * @nosideeffects
  * @template T
@@ -213,10 +216,20 @@ Object.isFrozen = function(obj) {};
 
 
 /**
+ * We acknowledge that this function does not exist on the `Object.prototype`
+ * and is declared in this file for other reasons.
+ *
+ * When `toJSON` is defined as a property on an object it can be used in
+ * conjunction with the JSON.stringify() function.
+ *
+ * It is defined here to:
+ * (1) Prevent the compiler from renaming the property on internal classes.
+ * (2) Enforce that the signature is correct for users defining it.
+ *
  * @param {string=} opt_key The JSON key for this object.
  * @return {*} The serializable representation of this object. Note that this
  *     need not be a string. See http://goo.gl/PEUvs.
- * @see https://es5.github.io/#x15.12.3
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify#toJSON()_behavior
  */
 Object.prototype.toJSON = function(opt_key) {};
 
@@ -238,7 +251,7 @@ Date.prototype.toJSON = function(opt_ignoredKey) {};
 
 /**
  * @param {string} jsonStr The string to parse.
- * @param {(function(string, *) : *)=} opt_reviver
+ * @param {(function(this:?, string, *) : *)=} opt_reviver
  * @return {*} The JSON object.
  * @throws {Error}
  */
@@ -247,7 +260,7 @@ JSON.parse = function(jsonStr, opt_reviver) {};
 
 /**
  * @param {*} jsonObj Input object.
- * @param {(Array<string>|(function(string, *) : *)|null)=} opt_replacer
+ * @param {(Array<string>|(function(this:?, string, *) : *)|null)=} opt_replacer
  * @param {(number|string)=} opt_space
  * @return {string} JSON string which represents jsonObj.
  * @throws {Error}
diff --git a/javascript/externs/es/es6.js b/javascript/externs/es/es6.js
index 08e2a47c2701..5222bd124b5b 100644
--- a/javascript/externs/es/es6.js
+++ b/javascript/externs/es/es6.js
@@ -21,13 +21,21 @@
  * @externs
  */
 
-
+/**
+ * Some es6 definitions:
+ * Symbol, IIterableResult, Iterable, IteratorIterable, Iterator,
+ * IteratorIterable moved to es3 file, because some base type requires them, and
+ * we want to keep them together. If you add new externs related to those types
+ * define them together in the es3 file.
+ */
 
 /**
- * @constructor
+ * TODO(b/142881197): UNUSED_RETURN_T and UNUSED_NEXT_T are not yet used for
+ * anything. https://github.com/google/closure-compiler/issues/3489
+ * @interface
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Generator
- * @implements {IteratorIterable<VALUE>}
- * @template VALUE
+ * @extends {IteratorIterable<VALUE>}
+ * @template VALUE, UNUSED_RETURN_T, UNUSED_NEXT_T
  */
 function Generator() {}
 
@@ -51,9 +59,6 @@ Generator.prototype.return = function(value) {};
 Generator.prototype.throw = function(exception) {};
 
 
-// TODO(johnlenz): Array and Arguments should be Iterable.
-
-
 
 /**
  * @param {number} value
@@ -147,13 +152,12 @@ Math.sign = function(value) {};
 Math.cbrt = function(value) {};
 
 /**
- * @param {number} value1
  * @param {...number} var_args
  * @return {number}
  * @nosideeffects
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/hypot
  */
-Math.hypot = function(value1, var_args) {};
+Math.hypot = function(var_args) {};
 
 /**
  * @param {number} value1
@@ -172,6 +176,14 @@ Math.imul = function(value1, value2) {};
  */
 Math.clz32 = function(value) {};
 
+/**
+ * @param {number} value
+ * @return {number}
+ * @nosideeffects
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/fround
+ */
+Math.fround = function(value) {};
+
 
 /**
  * @param {*} a
@@ -180,7 +192,7 @@ Math.clz32 = function(value) {};
  * @nosideeffects
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/is
  */
-Object.is;
+Object.is = function(a, b) {};
 
 
 /**
@@ -195,6 +207,41 @@ Object.is;
  */
 Number.prototype.toLocaleString = function(opt_locales, opt_options) {};
 
+/**
+ * Returns the wrapped primitive value of this Number object.
+ * @return {number}
+ * @nosideeffects
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/valueOf
+ * @override
+ */
+Number.prototype.valueOf = function() {};
+
+
+/**
+ * Pads the end of the string so that it reaches the given length.
+ * NOTE: this is an ES2017 (ES8) extern.
+ *
+ * @param {number} targetLength The target length.
+ * @param {string=} opt_padString The string to pad with.
+ * @this {String|string}
+ * @return {string}
+ * @nosideeffects
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/padEnd
+ */
+String.prototype.padEnd = function(targetLength, opt_padString) {};
+
+/**
+ * Pads the start of the string so that it reaches the given length.
+ * NOTE: this is an ES2017 (ES8) extern.
+ *
+ * @param {number} targetLength The target length.
+ * @param {string=} opt_padString The string to pad with.
+ * @this {String|string}
+ * @return {string}
+ * @nosideeffects
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/padStart
+ */
+String.prototype.padStart = function(targetLength, opt_padString) {};
 
 /**
  * Repeats the string the given number of times.
@@ -279,6 +326,33 @@ String.prototype.endsWith = function(searchString, opt_position) {};
  */
 String.prototype.includes = function(searchString, opt_position) {};
 
+/**
+ * @this {String|string}
+ * @return {string}
+ * @nosideeffects
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/trimStart
+ */
+String.prototype.trimStart = function() {};
+
+
+/**
+ * @this {String|string}
+ * @return {string}
+ * @nosideeffects
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/trimEnd
+ */
+String.prototype.trimEnd = function() {};
+
+
+/**
+ * @this {String|string}
+ * @param {!RegExp|string} regexp
+ * @return {!IteratorIterable<!RegExpResult>}
+ * @nosideeffects
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/matchAll
+ */
+String.prototype.matchAll = function(regexp) {};
+
 
 /**
  * @see http://dev.w3.org/html5/postmsg/
@@ -289,7 +363,6 @@ function Transferable() {}
 /**
  * @param {number} length The length in bytes
  * @constructor
- * @noalias
  * @throws {Error}
  * @implements {Transferable}
  */
@@ -317,7 +390,6 @@ ArrayBuffer.isView = function(arg) {};
 
 /**
  * @constructor
- * @noalias
  */
 function ArrayBufferView() {}
 
@@ -331,6 +403,26 @@ ArrayBufferView.prototype.byteOffset;
 ArrayBufferView.prototype.byteLength;
 
 
+/**
+ * @param {number} length The length in bytes
+ * @constructor
+ * @throws {Error}
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer
+ */
+function SharedArrayBuffer(length) {}
+
+/** @type {number} */
+SharedArrayBuffer.prototype.byteLength;
+
+/**
+ * @param {number} begin
+ * @param {number=} opt_end
+ * @return {!SharedArrayBuffer}
+ * @nosideeffects
+ */
+SharedArrayBuffer.prototype.slice = function(begin, opt_end) {};
+
+
 /**
  * @typedef {!ArrayBuffer|!ArrayBufferView}
  */
@@ -424,6 +516,7 @@ TypedArray.prototype.findIndex = function(callback, opt_thisArg) {};
 TypedArray.prototype.forEach = function(callback, opt_thisArg) {};
 
 /**
+ * NOTE: this is an ES2016 (ES7) extern.
  * @param {number} searchElement
  * @param {number=} opt_fromIndex
  * @return {boolean}
@@ -479,7 +572,8 @@ TypedArray.prototype.length;
 TypedArray.prototype.map = function(callback, opt_thisArg) {};
 
 /**
- * @param {function((number|INIT|RET), number, number, !TypedArray) : RET} callback
+ * @param {function((number|INIT|RET), number, number, !TypedArray) : RET}
+ *     callback
  * @param {INIT=} opt_initialValue
  * @return {RET}
  * @template INIT,RET
@@ -489,7 +583,8 @@ TypedArray.prototype.map = function(callback, opt_thisArg) {};
 TypedArray.prototype.reduce = function(callback, opt_initialValue) {};
 
 /**
- * @param {function((number|INIT|RET), number, number, !TypedArray) : RET} callback
+ * @param {function((number|INIT|RET), number, number, !TypedArray) : RET}
+ *     callback
  * @param {INIT=} opt_initialValue
  * @return {RET}
  * @template INIT,RET
@@ -582,13 +677,12 @@ TypedArray.prototype.toString = function() {};
 TypedArray.prototype[Symbol.iterator] = function() {};
 
 /**
- * @param {number|ArrayBufferView|Array<number>|ArrayBuffer} length or array
- *     or buffer
+ * @param {number|ArrayBufferView|Array<number>|ArrayBuffer|SharedArrayBuffer}
+ *     length or array or buffer
  * @param {number=} opt_byteOffset
  * @param {number=} opt_length
  * @constructor
  * @extends {TypedArray}
- * @noalias
  * @throws {Error}
  * @modifies {arguments} If the user passes a backing array, then indexed
  *     accesses will modify the backing array. JSCompiler does not model
@@ -608,7 +702,7 @@ function Int8Array(length, opt_byteOffset, opt_length) {}
 Int8Array.BYTES_PER_ELEMENT;
 
 /**
- * @param {!Array<number>} source
+ * @param {string|!IArrayLike<number>|!Iterable<number>} source
  * @param {function(this:S, number): number=} opt_mapFn
  * @param {S=} opt_this
  * @template S
@@ -626,13 +720,12 @@ Int8Array.of = function(var_args) {};
 
 
 /**
- * @param {number|ArrayBufferView|Array<number>|ArrayBuffer} length or array
- *     or buffer
+ * @param {number|ArrayBufferView|Array<number>|ArrayBuffer|SharedArrayBuffer}
+ *     length or array or buffer
  * @param {number=} opt_byteOffset
  * @param {number=} opt_length
  * @constructor
  * @extends {TypedArray}
- * @noalias
  * @throws {Error}
  * @modifies {arguments}
  */
@@ -642,7 +735,7 @@ function Uint8Array(length, opt_byteOffset, opt_length) {}
 Uint8Array.BYTES_PER_ELEMENT;
 
 /**
- * @param {!Array<number>} source
+ * @param {string|!IArrayLike<number>|!Iterable<number>} source
  * @param {function(this:S, number): number=} opt_mapFn
  * @param {S=} opt_this
  * @template S
@@ -660,13 +753,12 @@ Uint8Array.of = function(var_args) {};
 
 
 /**
- * @param {number|ArrayBufferView|Array<number>|ArrayBuffer} length or array
- *     or buffer
+ * @param {number|ArrayBufferView|Array<number>|ArrayBuffer|SharedArrayBuffer}
+ *     length or array or buffer
  * @param {number=} opt_byteOffset
  * @param {number=} opt_length
  * @constructor
  * @extends {TypedArray}
- * @noalias
  * @throws {Error}
  * @modifies {arguments}
  */
@@ -676,7 +768,7 @@ function Uint8ClampedArray(length, opt_byteOffset, opt_length) {}
 Uint8ClampedArray.BYTES_PER_ELEMENT;
 
 /**
- * @param {!Array<number>} source
+ * @param {string|!IArrayLike<number>|!Iterable<number>} source
  * @param {function(this:S, number): number=} opt_mapFn
  * @param {S=} opt_this
  * @template S
@@ -703,13 +795,12 @@ var CanvasPixelArray;
 
 
 /**
- * @param {number|ArrayBufferView|Array<number>|ArrayBuffer} length or array
- *     or buffer
+ * @param {number|ArrayBufferView|Array<number>|ArrayBuffer|SharedArrayBuffer}
+ *     length or array or buffer
  * @param {number=} opt_byteOffset
  * @param {number=} opt_length
  * @constructor
  * @extends {TypedArray}
- * @noalias
  * @throws {Error}
  * @modifies {arguments}
  */
@@ -719,7 +810,7 @@ function Int16Array(length, opt_byteOffset, opt_length) {}
 Int16Array.BYTES_PER_ELEMENT;
 
 /**
- * @param {!Array<number>} source
+ * @param {string|!IArrayLike<number>|!Iterable<number>} source
  * @param {function(this:S, number): number=} opt_mapFn
  * @param {S=} opt_this
  * @template S
@@ -737,13 +828,12 @@ Int16Array.of = function(var_args) {};
 
 
 /**
- * @param {number|ArrayBufferView|Array<number>|ArrayBuffer} length or array
- *     or buffer
+ * @param {number|ArrayBufferView|Array<number>|ArrayBuffer|SharedArrayBuffer}
+ *     length or array or buffer
  * @param {number=} opt_byteOffset
  * @param {number=} opt_length
  * @constructor
  * @extends {TypedArray}
- * @noalias
  * @throws {Error}
  * @modifies {arguments}
  */
@@ -753,7 +843,7 @@ function Uint16Array(length, opt_byteOffset, opt_length) {}
 Uint16Array.BYTES_PER_ELEMENT;
 
 /**
- * @param {!Array<number>} source
+ * @param {string|!IArrayLike<number>|!Iterable<number>} source
  * @param {function(this:S, number): number=} opt_mapFn
  * @param {S=} opt_this
  * @template S
@@ -771,13 +861,12 @@ Uint16Array.of = function(var_args) {};
 
 
 /**
- * @param {number|ArrayBufferView|Array<number>|ArrayBuffer} length or array
- *     or buffer
+ * @param {number|ArrayBufferView|Array<number>|ArrayBuffer|SharedArrayBuffer}
+ *     length or array or buffer
  * @param {number=} opt_byteOffset
  * @param {number=} opt_length
  * @constructor
  * @extends {TypedArray}
- * @noalias
  * @throws {Error}
  * @modifies {arguments}
  */
@@ -787,7 +876,7 @@ function Int32Array(length, opt_byteOffset, opt_length) {}
 Int32Array.BYTES_PER_ELEMENT;
 
 /**
- * @param {!Array<number>} source
+ * @param {string|!IArrayLike<number>|!Iterable<number>} source
  * @param {function(this:S, number): number=} opt_mapFn
  * @param {S=} opt_this
  * @template S
@@ -805,13 +894,12 @@ Int32Array.of = function(var_args) {};
 
 
 /**
- * @param {number|ArrayBufferView|Array<number>|ArrayBuffer} length or array
- *     or buffer
+ * @param {number|ArrayBufferView|Array<number>|ArrayBuffer|SharedArrayBuffer}
+ *     length or array or buffer
  * @param {number=} opt_byteOffset
  * @param {number=} opt_length
  * @constructor
  * @extends {TypedArray}
- * @noalias
  * @throws {Error}
  * @modifies {arguments}
  */
@@ -821,7 +909,7 @@ function Uint32Array(length, opt_byteOffset, opt_length) {}
 Uint32Array.BYTES_PER_ELEMENT;
 
 /**
- * @param {!Array<number>} source
+ * @param {string|!IArrayLike<number>|!Iterable<number>} source
  * @param {function(this:S, number): number=} opt_mapFn
  * @param {S=} opt_this
  * @template S
@@ -839,13 +927,12 @@ Uint32Array.of = function(var_args) {};
 
 
 /**
- * @param {number|ArrayBufferView|Array<number>|ArrayBuffer} length or array
- *     or buffer
+ * @param {number|ArrayBufferView|Array<number>|ArrayBuffer|SharedArrayBuffer}
+ *     length or array or buffer
  * @param {number=} opt_byteOffset
  * @param {number=} opt_length
  * @constructor
  * @extends {TypedArray}
- * @noalias
  * @throws {Error}
  * @modifies {arguments}
  */
@@ -855,7 +942,7 @@ function Float32Array(length, opt_byteOffset, opt_length) {}
 Float32Array.BYTES_PER_ELEMENT;
 
 /**
- * @param {!Array<number>} source
+ * @param {string|!IArrayLike<number>|!Iterable<number>} source
  * @param {function(this:S, number): number=} opt_mapFn
  * @param {S=} opt_this
  * @template S
@@ -873,13 +960,12 @@ Float32Array.of = function(var_args) {};
 
 
 /**
- * @param {number|ArrayBufferView|Array<number>|ArrayBuffer} length or array
- *     or buffer
+ * @param {number|ArrayBufferView|Array<number>|ArrayBuffer|SharedArrayBuffer}
+ *     length or array or buffer
  * @param {number=} opt_byteOffset
  * @param {number=} opt_length
  * @constructor
  * @extends {TypedArray}
- * @noalias
  * @throws {Error}
  * @modifies {arguments}
  */
@@ -889,7 +975,7 @@ function Float64Array(length, opt_byteOffset, opt_length) {}
 Float64Array.BYTES_PER_ELEMENT;
 
 /**
- * @param {!Array<number>} source
+ * @param {string|!IArrayLike<number>|!Iterable<number>} source
  * @param {function(this:S, number): number=} opt_mapFn
  * @param {S=} opt_this
  * @template S
@@ -907,12 +993,76 @@ Float64Array.of = function(var_args) {};
 
 
 /**
- * @param {ArrayBuffer} buffer
+ * @param {number|ArrayBufferView|Array<bigint>|ArrayBuffer|SharedArrayBuffer}
+ *     lengthOrArrayOrBuffer
+ * @param {number=} byteOffset
+ * @param {number=} bufferLength
+ * @constructor
+ * @extends {TypedArray}
+ * @throws {Error}
+ * @modifies {arguments}
+ */
+function BigInt64Array(lengthOrArrayOrBuffer, byteOffset, bufferLength) {}
+
+/** @const {number} */
+BigInt64Array.BYTES_PER_ELEMENT;
+
+/**
+ * @param {string|!IArrayLike<bigint>|!Iterable<bigint>} source
+ * @param {function(this:S, bigint): bigint=} mapFn
+ * @param {S=} thisArg
+ * @template S
+ * @return {!BigInt64Array}
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from
+ */
+BigInt64Array.from = function(source, mapFn, thisArg) {};
+
+/**
+ * @param {...bigint} var_args
+ * @return {!BigInt64Array}
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/of
+ */
+BigInt64Array.of = function(var_args) {};
+
+
+/**
+ * @param {number|ArrayBufferView|Array<bigint>|ArrayBuffer|SharedArrayBuffer}
+ *     lengthOrArrayOrBuffer
+ * @param {number=} byteOffset
+ * @param {number=} bufferLength
+ * @constructor
+ * @extends {TypedArray}
+ * @throws {Error}
+ * @modifies {arguments}
+ */
+function BigUint64Array(lengthOrArrayOrBuffer, byteOffset, bufferLength) {}
+
+/** @const {number} */
+BigUint64Array.BYTES_PER_ELEMENT;
+
+/**
+ * @param {string|!IArrayLike<bigint>|!Iterable<bigint>} source
+ * @param {function(this:S, bigint): bigint=} mapFn
+ * @param {S=} thisArg
+ * @template S
+ * @return {!BigUint64Array}
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from
+ */
+BigUint64Array.from = function(source, mapFn, thisArg) {};
+
+/**
+ * @param {...bigint} var_args
+ * @return {!BigUint64Array}
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/of
+ */
+BigUint64Array.of = function(var_args) {};
+
+/**
+ * @param {ArrayBuffer|SharedArrayBuffer} buffer
  * @param {number=} opt_byteOffset
  * @param {number=} opt_byteLength
  * @constructor
  * @extends {ArrayBufferView}
- * @noalias
  * @throws {Error}
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Typed_arrays/DataView
  */
@@ -980,6 +1130,22 @@ DataView.prototype.getFloat32 = function(byteOffset, opt_littleEndian) {};
  */
 DataView.prototype.getFloat64 = function(byteOffset, opt_littleEndian) {};
 
+/**
+ * @param {number} byteOffset
+ * @param {boolean=} littleEndian
+ * @return {bigint}
+ * @throws {Error}
+ */
+DataView.prototype.getBigInt64 = function(byteOffset, littleEndian) {};
+
+/**
+ * @param {number} byteOffset
+ * @param {boolean=} littleEndian
+ * @return {bigint}
+ * @throws {Error}
+ */
+DataView.prototype.getBigUint64 = function(byteOffset, littleEndian) {};
+
 /**
  * @param {number} byteOffset
  * @param {number} value
@@ -1052,6 +1218,24 @@ DataView.prototype.setFloat32 = function(
 DataView.prototype.setFloat64 = function(
     byteOffset, value, opt_littleEndian) {};
 
+/**
+ * @param {number} byteOffset
+ * @param {bigint} value
+ * @param {boolean=} littleEndian
+ * @throws {Error}
+ * @return {undefined}
+ */
+DataView.prototype.setBigInt64 = function(byteOffset, value, littleEndian) {};
+
+/**
+ * @param {number} byteOffset
+ * @param {bigint} value
+ * @param {boolean=} littleEndian
+ * @throws {Error}
+ * @return {undefined}
+ */
+DataView.prototype.setBigUint64 = function(byteOffset, value, littleEndian) {};
+
 
 /**
  * @see https://github.com/promises-aplus/promises-spec
@@ -1066,6 +1250,7 @@ var Thenable;
  * {@see goog.Thenable} inherits from this making all promises
  * interoperate.
  * @interface
+ * @struct
  * @template TYPE
  */
 function IThenable() {}
@@ -1077,8 +1262,8 @@ function IThenable() {}
  * @return {RESULT}
  * @template VALUE
  *
- * When a Promise (or thenable) is returned from the fulfilled callback,
- * the result is the payload of that promise, not the promise itself.
+ * When a `Thenable` is fulfilled or rejected with another `Thenable`, the
+ * payload of the second is used as the payload of the first.
  *
  * @template RESULT := type('IThenable',
  *     cond(isUnknown(VALUE), unknown(),
@@ -1144,6 +1329,50 @@ Promise.reject = function(opt_error) {};
  */
 Promise.all = function(iterable) {};
 
+/**
+ * Record type representing a single element of the array value one gets from
+ * Promise.allSettled.
+ *
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/allSettled
+ * @record
+ * @template VALUE
+ */
+Promise.AllSettledResultElement = function() {};
+
+/**
+ * 'fulfilled' or 'rejected' to indicate the final state of the corresponding
+ * Promise.
+ * @type {string}
+ */
+Promise.AllSettledResultElement.prototype.status;
+
+/**
+ * Exists only if the status field is 'fulfilled'
+ * @type {VALUE|undefined}
+ */
+Promise.AllSettledResultElement.prototype.value;
+
+/**
+ * Exists only if the status field is 'rejected'
+ * @type {*|undefined}
+ */
+Promise.AllSettledResultElement.prototype.reason;
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/allSettled
+ * @param {!Iterable<VALUE>} iterable
+ * @return {!Promise<!Array<!Promise.AllSettledResultElement<RESULT>>>}
+ * @template VALUE
+ * @template RESULT := mapunion(VALUE, (V) =>
+ *     cond(isUnknown(V),
+ *         unknown(),
+ *         cond(isTemplatized(V) && sub(rawTypeOf(V), 'IThenable'),
+ *             templateTypeOf(V, 0),
+ *             cond(sub(V, 'Thenable'), unknown(), V))))
+ * =:
+ */
+Promise.allSettled = function(iterable) {};
+
 
 /**
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise
@@ -1167,8 +1396,8 @@ Promise.race = function(iterable) {};
  * @return {RESULT}
  * @template VALUE
  *
- * When a Promise (or thenable) is returned from the fulfilled callback,
- * the result is the payload of that promise, not the promise itself.
+ * When a `Thenable` is fulfilled or rejected with another `Thenable`, the
+ * payload of the second is used as the payload of the first.
  *
  * @template RESULT := type('Promise',
  *     cond(isUnknown(VALUE), unknown(),
@@ -1185,13 +1414,38 @@ Promise.prototype.then = function(opt_onFulfilled, opt_onRejected) {};
 
 
 /**
- * @param {function(*): RESULT} onRejected
- * @return {!Promise<RESULT>}
- * @template RESULT
+ * @param {function(*):VALUE} onRejected
+ * @return {!Promise<TYPE|RESULT>} A Promise of the original type or a possibly
+ *     a different type depending on whether the parent promise was rejected.
+ *
+ * @template VALUE
+ *
+ * When a `Thenable` is rejected with another `Thenable`, the payload of the
+ * second is used as the payload of the first.
+ *
+ * @template RESULT := cond(
+ *     isUnknown(VALUE),
+ *     unknown(),
+ *     mapunion(VALUE, (V) =>
+ *         cond(
+ *             isTemplatized(V) && sub(rawTypeOf(V), 'IThenable'),
+ *             templateTypeOf(V, 0),
+ *             cond(
+ *                 sub(V, 'Thenable'),
+ *                 unknown(),
+ *                 V))))
+ * =:
  */
 Promise.prototype.catch = function(onRejected) {};
 
 
+/**
+ * @param {function()} callback
+ * @return {!Promise<TYPE>}
+ */
+Promise.prototype.finally = function(callback) {};
+
+
 /**
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/of
  * @param {...T} var_args
@@ -1216,6 +1470,14 @@ Array.from = function(arrayLike, opt_mapFn, opt_this) {};
 Array.prototype.keys;
 
 
+/**
+ * @return {!IteratorIterable<T>}
+ * @nosideeffects
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/values
+ */
+Array.prototype.values;
+
+
 /**
  * @return {!IteratorIterable<!Array<number|T>>} Iterator of [key, value] pairs.
  */
@@ -1223,32 +1485,32 @@ Array.prototype.entries;
 
 
 /**
- * @param {!function(this:S, T, number, !Array<T>): boolean} predicate
+ * @param {function(this:S, T, number, !Array<T>): boolean} predicateFn
  * @param {S=} opt_this
  * @return {T|undefined}
  * @this {IArrayLike<T>|string}
  * @template T,S
  * @see http://www.ecma-international.org/ecma-262/6.0/#sec-array.prototype.find
  */
-Array.prototype.find = function(predicate, opt_this) {};
+Array.prototype.find = function(predicateFn, opt_this) {};
 
 
 /**
- * @param {!function(this:S, T, number, !Array<T>): boolean} predicate
+ * @param {function(this:S, T, number, !Array<T>): boolean} predicateFn
  * @param {S=} opt_this
  * @return {number}
  * @this {IArrayLike<T>|string}
  * @template T,S
  * @see http://www.ecma-international.org/ecma-262/6.0/#sec-array.prototype.findindex
  */
-Array.prototype.findIndex = function(predicate, opt_this) {};
+Array.prototype.findIndex = function(predicateFn, opt_this) {};
 
 
 /**
  * @param {T} value
  * @param {number=} opt_begin
  * @param {number=} opt_end
- * @return {!IArrayLike<T>}
+ * @return {!Array<T>}
  * @this {!IArrayLike<T>|string}
  * @template T
  * @see http://www.ecma-international.org/ecma-262/6.0/#sec-array.prototype.fill
@@ -1261,22 +1523,60 @@ Array.prototype.fill = function(value, opt_begin, opt_end) {};
  * @param {number} start
  * @param {number=} opt_end
  * @see http://www.ecma-international.org/ecma-262/6.0/#sec-array.prototype.copywithin
+ * @this {!IArrayLike<T>|string}
  * @template T
- * @return {!IArrayLike<T>}
+ * @return {!Array<T>}
  */
 Array.prototype.copyWithin = function(target, start, opt_end) {};
 
 
 /**
+ * NOTE: this is an ES2016 (ES7) extern.
  * @param {T} searchElement
  * @param {number=} opt_fromIndex
  * @return {boolean}
  * @this {!IArrayLike<T>|string}
  * @template T
+ * @nosideeffects
  * @see https://tc39.github.io/ecma262/#sec-array.prototype.includes
  */
 Array.prototype.includes = function(searchElement, opt_fromIndex) {};
 
+/**
+ * Generates an array by passing every element of this array to a callback that
+ * returns an array of zero or more elements to be added to the result.
+ *
+ * NOTE: The specified behavior of the method is that the callback can return
+ * either an Array, which will be flattened into the result, or a non-array,
+ * which will simply be included.
+ *
+ * However, while defining that in the type information here is possible it's
+ * very hard to understand both for humans and automated tools other than
+ * closure-compiler that process these files. Also, we think it's best to
+ * encourage writing callbacks that just always return an Array for the sake
+ * of readability.
+ *
+ * The polyfill for this method provided by closure-compiler does behave as
+ * defined in the specification, though.
+ *
+ * @param {function(this: THIS, T, number, !IArrayLike<T>): !Array<S>}
+ *     callback
+ * @param {THIS=} thisArg
+ * @return {!Array<S>}
+ * @this {!IArrayLike<T>}
+ * @template T, THIS, S
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/flatMap
+ */
+Array.prototype.flatMap = function(callback, thisArg) {};
+
+/**
+ * @param {number=} depth
+ * @return {!Array<S>}
+ * @this {!IArrayLike<T>}
+ * @template T, S
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/flat
+ */
+Array.prototype.flat = function(depth) {};
 
 /**
  * @param {!Object} obj
@@ -1316,9 +1616,9 @@ Number.MAX_SAFE_INTEGER;
 
 
 /**
- * Parse an integer. Use of {@code parseInt} without {@code base} is strictly
+ * Parse an integer. Use of `parseInt` without `base` is strictly
  * banned in Google. If you really want to parse octal or hex based on the
- * leader, then pass {@code undefined} as the base.
+ * leader, then pass `undefined` as the base.
  *
  * @param {string} string
  * @param {number|undefined} radix
@@ -1372,7 +1672,7 @@ Number.isSafeInteger = function(value) {};
 
 /**
  * @param {!Object} target
- * @param {...Object} var_args
+ * @param {...(Object|null|undefined)} var_args
  * @return {!Object}
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/assign
  */
@@ -1380,6 +1680,7 @@ Object.assign = function(target, var_args) {};
 
 /**
  * TODO(dbeam): find a better place for ES2017 externs like this one.
+ * NOTE: this is an ES2017 (ES8) extern.
  * @param {!Object<T>} obj
  * @return {!Array<T>} values
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/values
@@ -1389,6 +1690,7 @@ Object.assign = function(target, var_args) {};
 Object.values = function(obj) {};
 
 /**
+ * NOTE: this is an ES2017 (ES8) extern.
  * @param {!Object<T>} obj
  * @return {!Array<!Array<(string|T)>>} entries
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/entries
@@ -1397,6 +1699,23 @@ Object.values = function(obj) {};
  */
 Object.entries = function(obj) {};
 
+/**
+ * @param {!Iterable<*>} iter
+ * @return {!Object}
+ * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/fromEntries
+ */
+Object.fromEntries = function(iter) {};
+
+/**
+ * NOTE: this is an ES2017 (ES8) extern.
+ * @param {!Object} obj
+ * @return {!Object<!ObjectPropertyDescriptor>} descriptors
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/getOwnPropertyDescriptors
+ * @throws {Error}
+ * @template T
+ */
+Object.getOwnPropertyDescriptors = function(obj) {};
+
 
 
 /**
@@ -1406,29 +1725,30 @@ Object.entries = function(obj) {};
 var Reflect = {};
 
 /**
- * @param {function(this: THIS, ...?): RESULT} target
+ * @param {function(this: THIS, ...?): RESULT} targetFn
  * @param {THIS} thisArg
- * @param {!Array} argList
+ * @param {!Array<?>} argList
  * @return {RESULT}
  * @template THIS, RESULT
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/apply
  */
-Reflect.apply = function(target, thisArg, argList) {};
+Reflect.apply = function(targetFn, thisArg, argList) {};
 
 /**
- * @param {function(new: ?, ...?)} target
- * @param {!Array} argList
- * @param {function(new: TARGET, ...?)=} opt_newTarget
+ * @param {function(new: ?, ...?)} targetConstructorFn
+ * @param {!Array<?>} argList
+ * @param {function(new: TARGET, ...?)=} opt_newTargetConstructorFn
  * @return {TARGET}
  * @template TARGET
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/construct
  */
-Reflect.construct = function(target, argList, opt_newTarget) {};
+Reflect.construct = function(
+    targetConstructorFn, argList, opt_newTargetConstructorFn) {};
 
 /**
  * @param {!Object} target
  * @param {string} propertyKey
- * @param {!Object} attributes
+ * @param {!ObjectPropertyDescriptor} attributes
  * @return {boolean}
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/defineProperty
  */
@@ -1518,3 +1838,204 @@ Reflect.set = function(target, propertyKey, value, opt_receiver) {};
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/setPrototypeOf
  */
 Reflect.setPrototypeOf = function(target, proto) {};
+
+
+/**
+ * @const
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Atomics
+ */
+var Atomics = {};
+
+/**
+ * @param {!TypedArray} typedArray
+ * @param {number} index
+ * @param {number} value
+ * @return {number}
+ */
+Atomics.add = function(typedArray, index, value) {};
+
+/**
+ * @param {!TypedArray} typedArray
+ * @param {number} index
+ * @param {number} value
+ * @return {number}
+ */
+Atomics.and = function(typedArray, index, value) {};
+
+/**
+ * @param {!TypedArray} typedArray
+ * @param {number} index
+ * @param {number} expectedValue
+ * @param {number} replacementValue
+ * @return {number}
+ */
+Atomics.compareExchange = function(
+    typedArray, index, expectedValue, replacementValue) {};
+
+/**
+ * @param {!TypedArray} typedArray
+ * @param {number} index
+ * @param {number} value
+ * @return {number}
+ */
+Atomics.exchange = function(typedArray, index, value) {};
+
+/**
+ * @param {number} size
+ * @return {boolean}
+ */
+Atomics.isLockFree = function(size) {};
+
+/**
+ * @param {!TypedArray} typedArray
+ * @param {number} index
+ * @return {number}
+ */
+Atomics.load = function(typedArray, index) {};
+
+/**
+ * @param {!Int32Array} typedArray
+ * @param {number} index
+ * @param {number=} count
+ * @return {number}
+ */
+Atomics.notify = function(typedArray, index, count) {};
+
+/**
+ * @param {!TypedArray} typedArray
+ * @param {number} index
+ * @param {number} value
+ * @return {number}
+ */
+Atomics.or = function(typedArray, index, value) {};
+
+/**
+ * @param {!TypedArray} typedArray
+ * @param {number} index
+ * @param {number} value
+ * @return {number}
+ */
+Atomics.store = function(typedArray, index, value) {};
+
+/**
+ * @param {!TypedArray} typedArray
+ * @param {number} index
+ * @param {number} value
+ * @return {number}
+ */
+Atomics.sub = function(typedArray, index, value) {};
+
+/**
+ * @param {!Int32Array} typedArray
+ * @param {number} index
+ * @param {number} value
+ * @param {number=} timeout
+ * @return {String}
+ */
+Atomics.wait = function(typedArray, index, value, timeout) {};
+
+/**
+ * @param {!Int32Array} typedArray
+ * @param {number} index
+ * @param {number=} count
+ * @return {number}
+ */
+Atomics.wake = function(typedArray, index, count) {};
+
+/**
+ * @param {!TypedArray} typedArray
+ * @param {number} index
+ * @param {number} value
+ * @return {number}
+ */
+Atomics.xor = function(typedArray, index, value) {};
+
+
+/**
+ * TODO(b/142881197): UNUSED_RETURN_T and UNUSED_NEXT_T are not yet used for
+ * anything.
+ * https://github.com/google/closure-compiler/issues/3489
+ * @interface
+ * @template VALUE, UNUSED_RETURN_T, UNUSED_NEXT_T
+ * @see https://tc39.github.io/proposal-async-iteration/
+ */
+function AsyncIterator() {}
+
+/**
+ * @param {?=} opt_value
+ * @return {!Promise<!IIterableResult<VALUE>>}
+ */
+AsyncIterator.prototype.next;
+
+
+/**
+ * @interface
+ * @template VALUE
+ */
+function AsyncIterable() {}
+
+
+/**
+ * @return {!AsyncIterator<VALUE, ?, *>}
+ */
+AsyncIterable.prototype[Symbol.asyncIterator] = function() {};
+
+
+/**
+ * @interface
+ * @extends {AsyncIterator<VALUE, ?, *>}
+ * @extends {AsyncIterable<VALUE>}
+ * @template VALUE
+ * @see https://tc39.github.io/proposal-async-iteration/
+ */
+function AsyncIteratorIterable() {}
+
+/**
+ * TODO(b/142881197): UNUSED_RETURN_T and UNUSED_NEXT_T are not yet used for
+ * anything. https://github.com/google/closure-compiler/issues/3489
+ * @interface
+ * @see https://tc39.github.io/proposal-async-iteration/
+ * @extends {AsyncIteratorIterable<VALUE>}
+ * @template VALUE, UNUSED_RETURN_T, UNUSED_NEXT_T
+ */
+function AsyncGenerator() {}
+
+/**
+ * @param {?=} opt_value
+ * @return {!Promise<!IIterableResult<VALUE>>}
+ * @override
+ */
+AsyncGenerator.prototype.next = function(opt_value) {};
+
+/**
+ * @param {VALUE} value
+ * @return {!Promise<!IIterableResult<VALUE>>}
+ */
+AsyncGenerator.prototype.return = function(value) {};
+
+/**
+ * @param {?} exception
+ * @return {!Promise<!IIterableResult<VALUE>>}
+ */
+AsyncGenerator.prototype.throw = function(exception) {};
+
+/**
+ * @constructor
+ * @struct
+ * @param {TYPE} value
+ * @template TYPE
+ * @nosideeffects
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakRef
+ */
+function WeakRef(value) {}
+
+/**
+ * @return {TYPE}
+ * @nosideeffects
+ */
+WeakRef.prototype.deref = function() {};
+
+/**
+ * @type {!Global}
+ */
+var globalThis;
diff --git a/javascript/externs/es/es6_collections.js b/javascript/externs/es/es6_collections.js
index ce1456c9709b..9d8457053f09 100644
--- a/javascript/externs/es/es6_collections.js
+++ b/javascript/externs/es/es6_collections.js
@@ -27,24 +27,25 @@
  * @param {Iterable<!Array<KEY|VALUE>>|!Array<!Array<KEY|VALUE>>=} opt_iterable
  * @implements {Iterable<!Array<KEY|VALUE>>}
  * @template KEY, VALUE
+ * @nosideeffects
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map
  */
 function Map(opt_iterable) {}
 
 /** @return {void} */
-Map.prototype.clear;
+Map.prototype.clear = function() {};
 
 /**
  * @param {KEY} key
  * @return {boolean}
  */
-Map.prototype.delete;
+Map.prototype.delete = function(key) {};
 
 /**
  * @return {!IteratorIterable<!Array<KEY|VALUE>>}
  * @nosideeffects
  */
-Map.prototype.entries;
+Map.prototype.entries = function() {};
 
 /**
  * @param {function(this:THIS, VALUE, KEY, MAP)} callback
@@ -52,26 +53,27 @@ Map.prototype.entries;
  * @this {MAP}
  * @template MAP,THIS
  */
-Map.prototype.forEach;
+Map.prototype.forEach = function(callback, opt_thisArg) {};
 
 /**
  * @param {KEY} key
  * @return {VALUE}
  * @nosideeffects
  */
-Map.prototype.get;
+Map.prototype.get = function(key) {};
 
 /**
  * @param {KEY} key
  * @return {boolean}
  * @nosideeffects
  */
-Map.prototype.has;
+Map.prototype.has = function(key) {};
 
 /**
  * @return {!IteratorIterable<KEY>}
+ * @nosideeffects
  */
-Map.prototype.keys;
+Map.prototype.keys = function() {};
 
 /**
  * @param {KEY} key
@@ -80,7 +82,7 @@ Map.prototype.keys;
  * @this {THIS}
  * @template THIS
  */
-Map.prototype.set;
+Map.prototype.set = function(key, value) {};
 
 /**
  * @type {number}
@@ -92,7 +94,7 @@ Map.prototype.size;
  * @return {!IteratorIterable<VALUE>}
  * @nosideeffects
  */
-Map.prototype.values;
+Map.prototype.values = function() {};
 
 /**
  * @return {!Iterator<!Array<KEY|VALUE>>}
@@ -104,32 +106,33 @@ Map.prototype[Symbol.iterator] = function() {};
  * @constructor @struct
  * @param {Iterable<!Array<KEY|VALUE>>|!Array<!Array<KEY|VALUE>>=} opt_iterable
  * @template KEY, VALUE
+ * @nosideeffects
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap
  */
 function WeakMap(opt_iterable) {}
 
 /** @return {void} */
-WeakMap.prototype.clear;
+WeakMap.prototype.clear = function() {};
 
 /**
  * @param {KEY} key
  * @return {boolean}
  */
-WeakMap.prototype.delete;
+WeakMap.prototype.delete = function(key) {};
 
 /**
  * @param {KEY} key
  * @return {VALUE}
  * @nosideeffects
  */
-WeakMap.prototype.get;
+WeakMap.prototype.get = function(key) {};
 
 /**
  * @param {KEY} key
  * @return {boolean}
  * @nosideeffects
  */
-WeakMap.prototype.has;
+WeakMap.prototype.has = function(key) {};
 
 /**
  * @param {KEY} key
@@ -138,15 +141,14 @@ WeakMap.prototype.has;
  * @this {THIS}
  * @template THIS
  */
-WeakMap.prototype.set;
-
-
+WeakMap.prototype.set = function(key, value) {};
 
 /**
  * @constructor @struct
  * @param {Iterable<VALUE>|Array<VALUE>=} opt_iterable
  * @implements {Iterable<VALUE>}
  * @template VALUE
+ * @nosideeffects
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set
  */
 function Set(opt_iterable) {}
@@ -157,25 +159,25 @@ function Set(opt_iterable) {}
  * @this {THIS}
  * @template THIS
  */
-Set.prototype.add;
+Set.prototype.add = function(value) {};
 
 /**
  * @return {void}
  */
-Set.prototype.clear;
+Set.prototype.clear = function() {};
 
 /**
  * @param {VALUE} value
  * @return {boolean}
  */
-Set.prototype.delete;
+Set.prototype.delete = function(value) {};
 
 /**
  * @return {!IteratorIterable<!Array<VALUE>>} Where each array has two entries:
  *     [value, value]
  * @nosideeffects
  */
-Set.prototype.entries;
+Set.prototype.entries = function() {};
 
 /**
  * @param {function(this: THIS, VALUE, VALUE, SET)} callback
@@ -183,14 +185,14 @@ Set.prototype.entries;
  * @this {SET}
  * @template SET,THIS
  */
-Set.prototype.forEach;
+Set.prototype.forEach = function(callback, opt_thisArg) {};
 
 /**
  * @param {VALUE} value
  * @return {boolean}
  * @nosideeffects
  */
-Set.prototype.has;
+Set.prototype.has = function(value) {};
 
 /**
  * @type {number} (readonly)
@@ -201,13 +203,13 @@ Set.prototype.size;
  * @return {!IteratorIterable<VALUE>}
  * @nosideeffects
  */
-Set.prototype.keys;
+Set.prototype.keys = function() {};
 
 /**
  * @return {!IteratorIterable<VALUE>}
  * @nosideeffects
  */
-Set.prototype.values;
+Set.prototype.values = function() {};
 
 /**
  * @return {!Iterator<VALUE>}
@@ -220,6 +222,7 @@ Set.prototype[Symbol.iterator] = function() {};
  * @constructor @struct
  * @param {Iterable<VALUE>|Array<VALUE>=} opt_iterable
  * @template VALUE
+ * @nosideeffects
  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set
  */
 function WeakSet(opt_iterable) {}
@@ -230,22 +233,22 @@ function WeakSet(opt_iterable) {}
  * @this {THIS}
  * @template THIS
  */
-WeakSet.prototype.add;
+WeakSet.prototype.add = function(value) {};
 
 /**
  * @return {void}
  */
-WeakSet.prototype.clear;
+WeakSet.prototype.clear = function() {};
 
 /**
  * @param {VALUE} value
  * @return {boolean}
  */
-WeakSet.prototype.delete;
+WeakSet.prototype.delete = function(value) {};
 
 /**
  * @param {VALUE} value
  * @return {boolean}
  * @nosideeffects
  */
-WeakSet.prototype.has;
+WeakSet.prototype.has = function(value) {};
diff --git a/javascript/externs/es/intl.js b/javascript/externs/es/intl.js
index d1404872af30..eed3320b55f7 100644
--- a/javascript/externs/es/intl.js
+++ b/javascript/externs/es/intl.js
@@ -26,7 +26,7 @@ var Intl = {};
 
 /**
  * NOTE: this API is not from ecma402 and is subject to change.
- * @param {string|Array.<string>=} opt_locales
+ * @param {string|Array<string>=} opt_locales
  * @param {{type: (string|undefined)}=}
  *         opt_options
  * @constructor
@@ -35,6 +35,7 @@ Intl.v8BreakIterator = function(opt_locales, opt_options) {};
 
 /**
  * @param {string} text
+ * @return {undefined}
  */
 Intl.v8BreakIterator.prototype.adoptText = function(text) {};
 
@@ -60,7 +61,7 @@ Intl.v8BreakIterator.prototype.next = function() {};
 
 /**
  * @constructor
- * @param {string|Array.<string>=} opt_locales
+ * @param {string|Array<string>=} opt_locales
  * @param {{usage: (string|undefined), localeMatcher: (string|undefined),
  *     sensitivity: (string|undefined), ignorePunctuation: (boolean|undefined),
  *     numeric: (boolean|undefined), caseFirst: (string|undefined)}=}
@@ -69,8 +70,9 @@ Intl.v8BreakIterator.prototype.next = function() {};
 Intl.Collator = function(opt_locales, opt_options) {};
 
 /**
- * @param {Array.<string>} locales
+ * @param {Array<string>} locales
  * @param {{localeMatcher: (string|undefined)}=} opt_options
+ * @return {Array<string>}
  */
 Intl.Collator.supportedLocalesOf = function(locales, opt_options) {};
 
@@ -90,7 +92,7 @@ Intl.Collator.prototype.resolvedOptions = function() {};
 
 /**
  * @constructor
- * @param {string|Array.<string>=} opt_locales
+ * @param {string|Array<string>=} opt_locales
  * @param {{localeMatcher: (string|undefined), useGrouping: (boolean|undefined),
  *     numberingSystem: (string|undefined), style: (string|undefined),
  *     currency: (string|undefined), currencyDisplay: (string|undefined),
@@ -104,8 +106,9 @@ Intl.Collator.prototype.resolvedOptions = function() {};
 Intl.NumberFormat = function(opt_locales, opt_options) {};
 
 /**
- * @param {Array.<string>} locales
+ * @param {Array<string>} locales
  * @param {{localeMatcher: (string|undefined)}=} opt_options
+ * @return {Array<string>}
  */
 Intl.NumberFormat.supportedLocalesOf = function(locales, opt_options) {};
 
@@ -115,6 +118,13 @@ Intl.NumberFormat.supportedLocalesOf = function(locales, opt_options) {};
  */
 Intl.NumberFormat.prototype.format = function(num) {};
 
+/**
+ * @param {number} num
+ * @return {!Array<{type: string, value: string}>}
+ * @see http://www.ecma-international.org/ecma-402/#sec-intl.numberformat.prototype.formattoparts
+ */
+Intl.NumberFormat.prototype.formatToParts = function(num) {};
+
 /**
  * @return {{locale: string, numberingSystem: string, style: string,
  *     currency: (string|undefined), currencyDisplay: (string|undefined),
@@ -126,7 +136,7 @@ Intl.NumberFormat.prototype.resolvedOptions = function() {};
 
 /**
  * @constructor
- * @param {string|Array.<string>=} opt_locales
+ * @param {string|Array<string>=} opt_locales
  * @param {{localeMatcher: (string|undefined),
  *    formatMatcher: (string|undefined), calendar: (string|undefined),
  *    numberingSystem: (string|undefined), tz: (string|undefined),
@@ -140,17 +150,24 @@ Intl.NumberFormat.prototype.resolvedOptions = function() {};
 Intl.DateTimeFormat = function(opt_locales, opt_options) {};
 
 /**
- * @param {Array.<string>} locales
+ * @param {Array<string>} locales
  * @param {{localeMatcher: string}=} opt_options
+ * @return {Array<string>}
  */
 Intl.DateTimeFormat.supportedLocalesOf = function(locales, opt_options) {};
 
 /**
- * @param {number} date
+ * @param {(!Date|number)=} date
  * @return {string}
  */
 Intl.DateTimeFormat.prototype.format = function(date) {};
 
+/**
+ * @param {(!Date|number)=} date
+ * @return {Array<{type: string, value: string}>}
+ */
+Intl.DateTimeFormat.prototype.formatToParts = function(date) {};
+
 /**
  * @return {{locale: string, calendar: string, numberingSystem: string,
  *    timeZone: (string|undefined), weekday: (string|undefined),
@@ -161,3 +178,74 @@ Intl.DateTimeFormat.prototype.format = function(date) {};
  *    hour12: (boolean|undefined)}}
  */
 Intl.DateTimeFormat.prototype.resolvedOptions = function() {};
+
+/**
+ * @constructor
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/PluralRules#Syntax
+ * @param {string|Array<string>=} opt_locales
+ * @param {{localeMatcher: (string|undefined), type: (string|undefined)}=}
+ *         opt_options
+ */
+Intl.PluralRules = function(opt_locales, opt_options) {};
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/PluralRules/supportedLocalesOf#Syntax
+ * @param {Array<string>} locales
+ * @param {{localeMatcher: string}=} opt_options
+ * @return {Array<string>}
+ */
+Intl.PluralRules.supportedLocalesOf = function(locales, opt_options) {};
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/PluralRules/resolvedOptions#Syntax
+ * @return {{locale: string, pluralCategories: Array<string>, type: string}}
+ */
+Intl.PluralRules.prototype.resolvedOptions = function() {};
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/PluralRules/select#Syntax
+ * @param {number} number
+ * @return {string}
+ */
+Intl.PluralRules.prototype.select = function(number) {};
+
+/**
+ * @constructor
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RelativeTimeFormat#Syntax
+ * @param {string|Array<string>=} opt_locales
+ * @param {{localeMatcher: (string|undefined),
+ *    numeric: (string|undefined),
+ *    style: (string|undefined)}=}
+ *        opt_options
+ */
+Intl.RelativeTimeFormat = function(opt_locales, opt_options) {};
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RelativeTimeFormat/supportedLocalesOf#Syntax
+ * @param {Array<string>} locales
+ * @param {{localeMatcher: string}=} opt_options
+ * @return {Array<string>}
+ */
+Intl.RelativeTimeFormat.supportedLocalesOf = function(locales, opt_options) {};
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RelativeTimeFormat/format#Syntax
+ * @param {number} value
+ * @param {string} unit
+ * @return {string}
+ */
+Intl.RelativeTimeFormat.prototype.format = function(value, unit) {};
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RelativeTimeFormat/formatToParts#Syntax
+ * @param {number} value
+ * @param {string} unit
+ * @return {Array<string>}
+ */
+Intl.RelativeTimeFormat.prototype.formatToParts = function(value, unit) {};
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RelativeTimeFormat/resolvedOptions#Syntax
+ * @return {{locale: string, pluralCategories: Array<string>, type: string}}
+ */
+Intl.RelativeTimeFormat.prototype.resolvedOptions = function() {};

From be70510c64f4f15a49fd979f2ecd1e36c2e32d35 Mon Sep 17 00:00:00 2001
From: Erik Krogh Kristensen <erik-krogh@github.com>
Date: Wed, 20 Jan 2021 16:13:28 +0100
Subject: [PATCH 2/6] update jQuery extern

---
 javascript/externs/lib/jquery-3.2.js | 60 ++++++++++++++++++++++++----
 1 file changed, 52 insertions(+), 8 deletions(-)

diff --git a/javascript/externs/lib/jquery-3.2.js b/javascript/externs/lib/jquery-3.2.js
index a94876ef6d85..192b2732285a 100644
--- a/javascript/externs/lib/jquery-3.2.js
+++ b/javascript/externs/lib/jquery-3.2.js
@@ -200,7 +200,7 @@ jQuery.prototype.add = function(arg1, context) {};
 jQuery.prototype.addBack = function(arg1) {};
 
 /**
- * @param {(string|function(number,String))} arg1
+ * @param {(string|Array<string>|function(number,String))} arg1
  * @return {!jQuery}
  */
 jQuery.prototype.addClass = function(arg1) {};
@@ -305,8 +305,16 @@ jQuery.prototype.append = function(arg1, content) {};
 jQuery.prototype.appendTo = function(target) {};
 
 /**
- * @param {(string|Object<string,*>)} arg1
- * @param {(string|number|boolean|function(number,string))=} arg2
+ * Only call this method with the following combinations of arguments:
+ *   function(string, (string|number|undefined))
+ *   function(!Object<string, (string|number)>)
+ *   function(string, function(this:Element number,string):(string|number))
+ *
+ * See https://api.jquery.com/attr/#attr2
+ *
+ * @param {(string|!Object<string,(string|number)>)} arg1
+ * @param {(string|number|function(this:Element,number,string):(string|number))=}
+ *     arg2
  * @return {(string|!jQuery)}
  */
 jQuery.prototype.attr = function(arg1, arg2) {};
@@ -331,6 +339,7 @@ jQuery.prototype.bind = function(arg1, eventData, arg3) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "blur", handler ) instead.
  */
 jQuery.prototype.blur = function(arg1, handler) {};
 
@@ -408,6 +417,7 @@ jQuery.callbacks.prototype.remove = function(callbacks) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "change", handler ) instead.
  */
 jQuery.prototype.change = function(arg1, handler) {};
 
@@ -428,6 +438,7 @@ jQuery.prototype.clearQueue = function(queueName) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "click", handler ) instead.
  */
 jQuery.prototype.click = function(arg1, handler) {};
 
@@ -461,6 +472,14 @@ jQuery.contains = function(container, contained) {};
  */
 jQuery.prototype.contents = function() {};
 
+/**
+ * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
+ * @param {function(!jQuery.Event)=} handler
+ * @return {!jQuery}
+ * @deprecated Please use .on( "contextmenu", handler ) instead.
+ */
+jQuery.prototype.contextmenu = function(arg1, handler) {};
+
 /**
  * @param {(string|Object<string,*>)} arg1
  * @param {(string|number|function(number,*))=} arg2
@@ -491,6 +510,7 @@ jQuery.prototype.data = function(arg1, value) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "dblclick", handler ) instead.
  */
 jQuery.prototype.dblclick = function(arg1, handler) {};
 
@@ -845,7 +865,7 @@ jQuery.Event.prototype.type;
 /** @type {Window} */
 jQuery.Event.prototype.view;
 
-/** @type {number} */
+/** @type {number} @deprecated */
 jQuery.Event.prototype.which;
 
 /**
@@ -922,6 +942,7 @@ jQuery.fn = jQuery.prototype;
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "focus", handler ) instead.
  */
 jQuery.prototype.focus = function(arg1, handler) {};
 
@@ -929,6 +950,7 @@ jQuery.prototype.focus = function(arg1, handler) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "focusin", handler ) instead.
  */
 jQuery.prototype.focusin = function(arg1, handler) {};
 
@@ -936,6 +958,7 @@ jQuery.prototype.focusin = function(arg1, handler) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "focusout", handler ) instead.
  */
 jQuery.prototype.focusout = function(arg1, handler) {};
 
@@ -1040,6 +1063,7 @@ jQuery.holdReady = function(hold) {};
  * @param {function(!jQuery.Event)} arg1
  * @param {function(!jQuery.Event)=} handlerOut
  * @return {!jQuery}
+ * @deprecated Please use .on( "mouseenter", handler ) and .on( "mouseleave", handler ) instead.
  */
 jQuery.prototype.hover = function(arg1, handlerOut) {};
 
@@ -1121,6 +1145,7 @@ jQuery.isEmptyObject = function(obj) {};
  * @param {*} obj
  * @return {boolean}
  * @nosideeffects
+ * @deprecated
  */
 jQuery.isFunction = function(obj) {};
 
@@ -1128,6 +1153,7 @@ jQuery.isFunction = function(obj) {};
  * @param {*} value
  * @return {boolean}
  * @nosideeffects
+ * @deprecated
  */
 jQuery.isNumeric = function(value) {};
 
@@ -1142,6 +1168,7 @@ jQuery.isPlainObject = function(obj) {};
  * @param {*} obj
  * @return {boolean}
  * @nosideeffects
+ * @deprecated
  */
 jQuery.isWindow = function(obj) {};
 
@@ -1262,6 +1289,7 @@ jQuery.jqXHR.prototype.then =
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "keydown", handler ) instead.
  */
 jQuery.prototype.keydown = function(arg1, handler) {};
 
@@ -1269,6 +1297,7 @@ jQuery.prototype.keydown = function(arg1, handler) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "keypress", handler ) instead.
  */
 jQuery.prototype.keypress = function(arg1, handler) {};
 
@@ -1276,6 +1305,7 @@ jQuery.prototype.keypress = function(arg1, handler) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "keyup", handler ) instead.
  */
 jQuery.prototype.keyup = function(arg1, handler) {};
 
@@ -1290,7 +1320,7 @@ jQuery.prototype.length;
 
 /**
  * @param {*} obj
- * @return {Array<*>}
+ * @return {!Array<*>}
  * @nosideeffects
  */
 jQuery.makeArray = function(obj) {};
@@ -1320,6 +1350,7 @@ jQuery.merge = function(first, second) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "mousedown", handler ) instead.
  */
 jQuery.prototype.mousedown = function(arg1, handler) {};
 
@@ -1327,6 +1358,7 @@ jQuery.prototype.mousedown = function(arg1, handler) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "mousenter", handler ) instead.
  */
 jQuery.prototype.mouseenter = function(arg1, handler) {};
 
@@ -1334,6 +1366,7 @@ jQuery.prototype.mouseenter = function(arg1, handler) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "mouseleave", handler ) instead.
  */
 jQuery.prototype.mouseleave = function(arg1, handler) {};
 
@@ -1341,6 +1374,7 @@ jQuery.prototype.mouseleave = function(arg1, handler) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "mousemove", handler ) instead.
  */
 jQuery.prototype.mousemove = function(arg1, handler) {};
 
@@ -1348,6 +1382,7 @@ jQuery.prototype.mousemove = function(arg1, handler) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "mouseout", handler ) instead.
  */
 jQuery.prototype.mouseout = function(arg1, handler) {};
 
@@ -1355,6 +1390,7 @@ jQuery.prototype.mouseout = function(arg1, handler) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "mouseover", handler ) instead.
  */
 jQuery.prototype.mouseover = function(arg1, handler) {};
 
@@ -1362,6 +1398,7 @@ jQuery.prototype.mouseover = function(arg1, handler) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "mouseup", handler ) instead.
  */
 jQuery.prototype.mouseup = function(arg1, handler) {};
 
@@ -1389,7 +1426,7 @@ jQuery.prototype.nextUntil = function(arg1, filter) {};
 
 /**
  * @param {boolean=} removeAll
- * @return {Object}
+ * @return {!typeof jQuery}
  */
 jQuery.noConflict = function(removeAll) {};
 
@@ -1408,6 +1445,7 @@ jQuery.prototype.not = function(arg1) {};
 /**
  * @return {number}
  * @nosideeffects
+ * @deprecated
  */
 jQuery.now = function() {};
 
@@ -1655,6 +1693,7 @@ jQuery.prototype.prop = function(arg1, arg2) {};
 /**
  * @param {...*} var_args
  * @return {function()}
+ * @deprecated
  */
 jQuery.proxy = function(var_args) {};
 
@@ -1709,7 +1748,7 @@ jQuery.prototype.remove = function(selector) {};
 jQuery.prototype.removeAttr = function(attributeName) {};
 
 /**
- * @param {(string|function(number,string))=} arg1
+ * @param {(string|Array<string>|function(number,string))=} arg1
  * @return {!jQuery}
  */
 jQuery.prototype.removeClass = function(arg1) {};
@@ -1749,6 +1788,7 @@ jQuery.prototype.replaceWith = function(arg1) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "resize", handler ) instead.
  */
 jQuery.prototype.resize = function(arg1, handler) {};
 
@@ -1756,6 +1796,7 @@ jQuery.prototype.resize = function(arg1, handler) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "scroll", handler ) instead.
  */
 jQuery.prototype.scroll = function(arg1, handler) {};
 
@@ -1775,6 +1816,7 @@ jQuery.prototype.scrollTop = function(value) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "select", handler ) instead.
  */
 jQuery.prototype.select = function(arg1, handler) {};
 
@@ -1859,6 +1901,7 @@ jQuery.prototype.stop = function(arg1, arg2, jumpToEnd) {};
  * @param {(function(!jQuery.Event)|Object<string, *>)=} arg1
  * @param {function(!jQuery.Event)=} handler
  * @return {!jQuery}
+ * @deprecated Please use .on( "submit", handler ) instead.
  */
 jQuery.prototype.submit = function(arg1, handler) {};
 
@@ -1932,7 +1975,7 @@ jQuery.prototype.toArray = function() {};
 jQuery.prototype.toggle = function(arg1, arg2, arg3) {};
 
 /**
- * @param {(string|function(number,string,boolean))} arg1
+ * @param {(string|Array<string>|function(number,string,boolean))} arg1
  * @param {boolean=} flag
  * @return {!jQuery}
  */
@@ -1963,6 +2006,7 @@ jQuery.trim = function(str) {};
  * @param {*} obj
  * @return {string}
  * @nosideeffects
+ * @deprecated
  */
 jQuery.type = function(obj) {};
 

From bcd7af395ec0a3d4b09d6c21a437b725397e2836 Mon Sep 17 00:00:00 2001
From: Erik Krogh Kristensen <erik-krogh@github.com>
Date: Wed, 20 Jan 2021 17:46:41 +0100
Subject: [PATCH 3/6] update V8 extern

---
 javascript/externs/vm/v8.js | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/javascript/externs/vm/v8.js b/javascript/externs/vm/v8.js
index be11bd83a557..2652c0601aed 100644
--- a/javascript/externs/vm/v8.js
+++ b/javascript/externs/vm/v8.js
@@ -28,6 +28,15 @@
 function CallSite() {}
 
 
+/**
+ * Runs the garbage collector, provided that you start V8 with --expose-gc or
+ * Chrome with --js-flags="--expose-gc".
+ * See https://v8.dev/docs/memory-leaks
+ * @type {undefined|function()}
+ */
+CallSite.prototype.gc;
+
+
 /**
  * Returns the value of this.
  * @return {Object|undefined}

From 067dab4d29279fa8b77a5e6defb1c85ca8d7c1f7 Mon Sep 17 00:00:00 2001
From: Erik Krogh Kristensen <erik-krogh@github.com>
Date: Wed, 20 Jan 2021 18:18:31 +0100
Subject: [PATCH 4/6] remove duplicate externs

---
 javascript/externs/web/intl.js         | 167 -------------------------
 javascript/externs/web/w3c_encoding.js |  54 --------
 2 files changed, 221 deletions(-)
 delete mode 100644 javascript/externs/web/intl.js
 delete mode 100644 javascript/externs/web/w3c_encoding.js

diff --git a/javascript/externs/web/intl.js b/javascript/externs/web/intl.js
deleted file mode 100644
index a70f9bad2a92..000000000000
--- a/javascript/externs/web/intl.js
+++ /dev/null
@@ -1,167 +0,0 @@
-/*
- * Copyright 2013 The Closure Compiler Authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-/**
- * @fileoverview Definitions for the JS Internationalization API as defined in
- * http://www.ecma-international.org/ecma-402/1.0/
- *
- * @externs
- */
-
-/** @const */
-var Intl = {};
-
-/**
- * NOTE: this API is not from ecma402 and is subject to change.
- * @param {string|Array<string>=} opt_locales
- * @param {{type: (string|undefined)}=}
- *         opt_options
- * @constructor
- */
-Intl.v8BreakIterator = function(opt_locales, opt_options) {};
-
-/**
- * @param {string} text
- * @return {undefined}
- */
-Intl.v8BreakIterator.prototype.adoptText = function(text) {};
-
-/**
- * @return {string}
- */
-Intl.v8BreakIterator.prototype.breakType = function() {};
-
-/**
- * @return {number}
- */
-Intl.v8BreakIterator.prototype.current = function() {};
-
-/**
- * @return {number}
- */
-Intl.v8BreakIterator.prototype.first = function() {};
-
-/**
- * @return {number}
- */
-Intl.v8BreakIterator.prototype.next = function() {};
-
-/**
- * @constructor
- * @param {string|Array<string>=} opt_locales
- * @param {{usage: (string|undefined), localeMatcher: (string|undefined),
- *     sensitivity: (string|undefined), ignorePunctuation: (boolean|undefined),
- *     numeric: (boolean|undefined), caseFirst: (string|undefined)}=}
- *         opt_options
- */
-Intl.Collator = function(opt_locales, opt_options) {};
-
-/**
- * @param {Array<string>} locales
- * @param {{localeMatcher: (string|undefined)}=} opt_options
- * @return {Array<string>}
- */
-Intl.Collator.supportedLocalesOf = function(locales, opt_options) {};
-
-/**
- * @param {string} arg1
- * @param {string} arg2
- * @return {number}
- */
-Intl.Collator.prototype.compare = function(arg1, arg2) {};
-
-/**
- * @return {{locale: string, usage: string, sensitivity: string,
- *     ignorePunctuation: boolean, collation: string, numeric: boolean,
- *     caseFirst: string}}
- */
-Intl.Collator.prototype.resolvedOptions = function() {};
-
-/**
- * @constructor
- * @param {string|Array<string>=} opt_locales
- * @param {{localeMatcher: (string|undefined), useGrouping: (boolean|undefined),
- *     numberingSystem: (string|undefined), style: (string|undefined),
- *     currency: (string|undefined), currencyDisplay: (string|undefined),
- *     minimumIntegerDigits: (number|undefined),
- *     minimumFractionDigits: (number|undefined),
- *     maximumFractionDigits: (number|undefined),
- *     minimumSignificantDigits: (number|undefined),
- *     maximumSignificantDigits: (number|undefined)}=}
- *         opt_options
- */
-Intl.NumberFormat = function(opt_locales, opt_options) {};
-
-/**
- * @param {Array<string>} locales
- * @param {{localeMatcher: (string|undefined)}=} opt_options
- * @return {Array<string>}
- */
-Intl.NumberFormat.supportedLocalesOf = function(locales, opt_options) {};
-
-/**
- * @param {number} num
- * @return {string}
- */
-Intl.NumberFormat.prototype.format = function(num) {};
-
-/**
- * @return {{locale: string, numberingSystem: string, style: string,
- *     currency: (string|undefined), currencyDisplay: (string|undefined),
- *     minimumIntegerDigits: number, minimumFractionDigits: number,
- *     maximumFractionDigits: number, minimumSignificantDigits: number,
- *     maximumSignificantDigits: number, useGrouping: boolean}}
- */
-Intl.NumberFormat.prototype.resolvedOptions = function() {};
-
-/**
- * @constructor
- * @param {string|Array<string>=} opt_locales
- * @param {{localeMatcher: (string|undefined),
- *    formatMatcher: (string|undefined), calendar: (string|undefined),
- *    numberingSystem: (string|undefined), tz: (string|undefined),
- *    weekday: (string|undefined), era: (string|undefined),
- *    year: (string|undefined), month: (string|undefined),
- *    day: (string|undefined), hour: (string|undefined),
- *    minute: (string|undefined), second: (string|undefined),
- *    timeZoneName: (string|undefined), hour12: (boolean|undefined)}=}
- *        opt_options
- */
-Intl.DateTimeFormat = function(opt_locales, opt_options) {};
-
-/**
- * @param {Array<string>} locales
- * @param {{localeMatcher: string}=} opt_options
- * @return {Array<string>}
- */
-Intl.DateTimeFormat.supportedLocalesOf = function(locales, opt_options) {};
-
-/**
- * @param {(!Date|number)=} date
- * @return {string}
- */
-Intl.DateTimeFormat.prototype.format = function(date) {};
-
-/**
- * @return {{locale: string, calendar: string, numberingSystem: string,
- *    timeZone: (string|undefined), weekday: (string|undefined),
- *    era: (string|undefined), year: (string|undefined),
- *    month: (string|undefined), day: (string|undefined),
- *    hour: (string|undefined), minute: (string|undefined),
- *    second: (string|undefined), timeZoneName: (string|undefined),
- *    hour12: (boolean|undefined)}}
- */
-Intl.DateTimeFormat.prototype.resolvedOptions = function() {};
diff --git a/javascript/externs/web/w3c_encoding.js b/javascript/externs/web/w3c_encoding.js
deleted file mode 100644
index 947821a90979..000000000000
--- a/javascript/externs/web/w3c_encoding.js
+++ /dev/null
@@ -1,54 +0,0 @@
-/*
- * Copyright 2015 The Closure Compiler Authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-/**
- * @fileoverview Definitions for W3C's Encoding specification
- *     https://encoding.spec.whatwg.org
- * @externs
- */
-
-/**
- * @constructor
- * @param {string=} encoding
- * @param {Object=} options
- */
-function TextDecoder(encoding, options) {}
-
-/** @type {string} **/ TextDecoder.prototype.encoding;
-/** @type {boolean} **/ TextDecoder.prototype.fatal;
-/** @type {boolean} **/ TextDecoder.prototype.ignoreBOM;
-
-/**
- * @param {!Uint8Array} input
- * @param {Object=} options
- * @return {string}
- */
-TextDecoder.prototype.decode = function decode(input, options) {};
-
-/**
- * @constructor
- * @param {string=} encoding
- * @param {Object=} options
- */
-function TextEncoder(encoding, options) {}
-
-/** @type {string} **/ TextEncoder.prototype.encoding;
-
-/**
- * @param {string} input
- * @return {!Uint8Array}
- */
-TextEncoder.prototype.encode = function(input) {};

From 24517abdffaf79eea30f161cde0b50e40c5c3444 Mon Sep 17 00:00:00 2001
From: Erik Krogh Kristensen <erik-krogh@github.com>
Date: Wed, 20 Jan 2021 18:19:12 +0100
Subject: [PATCH 5/6] add new externs to web

---
 javascript/externs/web/es6_proxy.js           |  143 +
 javascript/externs/web/fido.js                |   94 +
 javascript/externs/web/google_legacy.js       |   31 +
 .../externs/web/intersection_observer.js      |  178 ++
 javascript/externs/web/mediakeys.js           |  305 ++
 .../externs/web/nonstandard_anim_timing.js    |   97 +
 javascript/externs/web/nonstandard_audio.js   |   82 +
 javascript/externs/web/nonstandard_console.js |   66 +
 .../externs/web/nonstandard_indexeddb.js      |   78 +
 .../web/nonstandard_navigation_timing.js      |   38 +
 javascript/externs/web/nonstandard_rtc.js     |   44 +
 .../externs/web/nonstandard_selection.js      |   80 +
 javascript/externs/web/w3c_abort.js           |   50 +
 javascript/externs/web/w3c_audio.js           | 1587 ++++++++++
 javascript/externs/web/w3c_clipboard.js       |   40 +
 javascript/externs/web/w3c_clipboardevent.js  |   47 +
 .../externs/web/w3c_composition_event.js      |   93 +
 javascript/externs/web/w3c_eventsource.js     |  110 +
 javascript/externs/web/w3c_fileapi.js         |  295 ++
 javascript/externs/web/w3c_geometry1.js       |  899 ++++++
 javascript/externs/web/w3c_keyboardlock.js    |   47 +
 .../externs/web/w3c_mediacapabilities.js      |  206 ++
 javascript/externs/web/w3c_netinfo.js         |   85 +
 javascript/externs/web/w3c_payment_request.js |  401 +++
 javascript/externs/web/w3c_pointerlock.js     |   63 +
 javascript/externs/web/w3c_referrer_policy.js |   36 +
 .../externs/web/w3c_screen_wake_lock.js       |   58 +
 javascript/externs/web/w3c_selection.js       |  209 ++
 javascript/externs/web/w3c_speech.js          |  412 +++
 javascript/externs/web/w3c_trusted_types.js   |  139 +
 javascript/externs/web/w3c_vibration.js       |   38 +
 javascript/externs/web/w3c_worklets.js        |   54 +
 javascript/externs/web/web_animations.js      |  362 +++
 javascript/externs/web/web_app_manifest.js    |   50 +
 javascript/externs/web/webassembly.js         |  176 ++
 javascript/externs/web/webgl2.js              | 2727 +++++++++++++++++
 javascript/externs/web/webgl2_compute.js      | 1609 ++++++++++
 javascript/externs/web/whatwg_console.js      |  152 +
 .../externs/web/wicg_file_system_access.js    |  331 ++
 javascript/externs/web/wicg_floc.js           |   27 +
 javascript/externs/web/wicg_resizeobserver.js |   77 +
 javascript/externs/web/wicg_trust_token.js    |   89 +
 javascript/externs/web/wicg_uach.js           |   85 +
 43 files changed, 11790 insertions(+)
 create mode 100644 javascript/externs/web/es6_proxy.js
 create mode 100644 javascript/externs/web/fido.js
 create mode 100644 javascript/externs/web/google_legacy.js
 create mode 100644 javascript/externs/web/intersection_observer.js
 create mode 100644 javascript/externs/web/mediakeys.js
 create mode 100644 javascript/externs/web/nonstandard_anim_timing.js
 create mode 100644 javascript/externs/web/nonstandard_audio.js
 create mode 100644 javascript/externs/web/nonstandard_console.js
 create mode 100644 javascript/externs/web/nonstandard_indexeddb.js
 create mode 100644 javascript/externs/web/nonstandard_navigation_timing.js
 create mode 100644 javascript/externs/web/nonstandard_rtc.js
 create mode 100644 javascript/externs/web/nonstandard_selection.js
 create mode 100644 javascript/externs/web/w3c_abort.js
 create mode 100644 javascript/externs/web/w3c_audio.js
 create mode 100644 javascript/externs/web/w3c_clipboard.js
 create mode 100644 javascript/externs/web/w3c_clipboardevent.js
 create mode 100644 javascript/externs/web/w3c_composition_event.js
 create mode 100644 javascript/externs/web/w3c_eventsource.js
 create mode 100644 javascript/externs/web/w3c_fileapi.js
 create mode 100644 javascript/externs/web/w3c_geometry1.js
 create mode 100644 javascript/externs/web/w3c_keyboardlock.js
 create mode 100644 javascript/externs/web/w3c_mediacapabilities.js
 create mode 100644 javascript/externs/web/w3c_netinfo.js
 create mode 100644 javascript/externs/web/w3c_payment_request.js
 create mode 100644 javascript/externs/web/w3c_pointerlock.js
 create mode 100644 javascript/externs/web/w3c_referrer_policy.js
 create mode 100644 javascript/externs/web/w3c_screen_wake_lock.js
 create mode 100644 javascript/externs/web/w3c_selection.js
 create mode 100644 javascript/externs/web/w3c_speech.js
 create mode 100644 javascript/externs/web/w3c_trusted_types.js
 create mode 100644 javascript/externs/web/w3c_vibration.js
 create mode 100644 javascript/externs/web/w3c_worklets.js
 create mode 100644 javascript/externs/web/web_animations.js
 create mode 100644 javascript/externs/web/web_app_manifest.js
 create mode 100644 javascript/externs/web/webassembly.js
 create mode 100644 javascript/externs/web/webgl2.js
 create mode 100644 javascript/externs/web/webgl2_compute.js
 create mode 100644 javascript/externs/web/whatwg_console.js
 create mode 100644 javascript/externs/web/wicg_file_system_access.js
 create mode 100644 javascript/externs/web/wicg_floc.js
 create mode 100644 javascript/externs/web/wicg_resizeobserver.js
 create mode 100644 javascript/externs/web/wicg_trust_token.js
 create mode 100644 javascript/externs/web/wicg_uach.js

diff --git a/javascript/externs/web/es6_proxy.js b/javascript/externs/web/es6_proxy.js
new file mode 100644
index 000000000000..21fc96d86cde
--- /dev/null
+++ b/javascript/externs/web/es6_proxy.js
@@ -0,0 +1,143 @@
+/*
+ * Copyright 2018 The Closure Compiler Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for ECMAScript 6 Proxy objects.
+ * @see https://tc39.github.io/ecma262/#sec-proxy-objects
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy
+ * @externs
+ */
+
+
+/**
+ * @record
+ * @template TARGET
+ * @see https://tc39.github.io/ecma262/#sec-proxy-object-internal-methods-and-internal-slots
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler
+ */
+function ProxyHandler() {}
+
+/**
+ * @type {(function(TARGET):?Object)|undefined}
+ * @see https://tc39.github.io/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-getprototypeof
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/getPrototypeOf
+ */
+ProxyHandler.prototype.getPrototypeOf /* = function(target) {} */;
+
+/**
+ * @type {(function(TARGET, ?Object):boolean)|undefined}
+ * @see https://tc39.github.io/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-setprototypeof-v
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/setPrototypeOf
+ */
+ProxyHandler.prototype.setPrototypeOf /* = function(target, proto) {} */;
+
+/**
+ * @type {(function(TARGET):boolean)|undefined}
+ * @see https://tc39.github.io/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-isextensible
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/isExtensible
+ */
+ProxyHandler.prototype.isExtensible /* = function(target) {} */;
+
+/**
+ * @type {(function(TARGET):boolean)|undefined}
+ * @see https://tc39.github.io/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-preventextensions
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/preventExtensions
+ */
+ProxyHandler.prototype.preventExtensions /* = function(target) {} */;
+
+/**
+ * @type {(function(TARGET, (string|symbol)):(!ObjectPropertyDescriptor|undefined))|undefined}
+ * @see https://tc39.github.io/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-getownproperty-p
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/getOwnPropertyDescriptor
+ */
+ProxyHandler.prototype.getOwnPropertyDescriptor /* = function(target, prop) {} */;
+
+/**
+ * @type {(function(TARGET, (string|symbol), !ObjectPropertyDescriptor):boolean)|undefined}
+ * @see https://tc39.github.io/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-defineownproperty-p-desc
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/defineProperty
+ */
+ProxyHandler.prototype.defineProperty /* = function(target, prop, desc) {} */;
+
+/**
+ * @type {(function(TARGET, (string|symbol)):boolean)|undefined}
+ * @see https://tc39.github.io/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-hasproperty-p
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/has
+ */
+ProxyHandler.prototype.has /* = function(target, prop) {} */;
+
+/**
+ * @type {(function(TARGET, (string|symbol), !Object):*)|undefined}
+ * @see https://tc39.github.io/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-get-p-receiver
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/get
+ */
+ProxyHandler.prototype.get /* = function(target, prop, receiver) {} */;
+
+/**
+ * @type {(function(TARGET, (string|symbol), *, !Object):boolean)|undefined}
+ * @see https://tc39.github.io/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-set-p-v-receiver
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/set
+ */
+ProxyHandler.prototype.set /* = function(target, prop, value, receiver) {} */;
+
+/**
+ * @type {(function(TARGET, (string|symbol)):boolean)|undefined}
+ * @see https://tc39.github.io/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-delete-p
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/deleteProperty
+ */
+ProxyHandler.prototype.deleteProperty /* = function (target, prop) {} */;
+
+/**
+ * @type {(function(TARGET):!Array<(string|symbol)>)|undefined}
+ * @see https://tc39.github.io/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-ownpropertykeys
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/ownKeys
+ */
+ProxyHandler.prototype.ownKeys /* = function(target) {} */;
+
+/**
+ * @type {(function(TARGET, *, !Array):*)|undefined}
+ * @see https://tc39.github.io/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-call-thisargument-argumentslist
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/apply
+ */
+ProxyHandler.prototype.apply /* = function(target, thisArg, argList) {} */;
+
+/**
+ * @type {(function(TARGET, !Array, function(new: ?, ...?)):!Object)|undefined}
+ * @see https://tc39.github.io/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-construct-argumentslist-newtarget
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/construct
+ */
+ProxyHandler.prototype.construct /* = function(target, argList, newTarget) {} */;
+
+
+/**
+ * @constructor
+ * @param {TARGET} target
+ * @param {!ProxyHandler<TARGET>} handler
+ * @template TARGET
+ * @see https://tc39.github.io/ecma262/#sec-proxy-constructor
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy#Syntax
+ */
+function Proxy(target, handler) {}
+
+/**
+ * @param {TARGET} target
+ * @param {!ProxyHandler<TARGET>} handler
+ * @return {{proxy: !Proxy<TARGET>, revoke: function():void}}
+ * @template TARGET
+ * @see https://tc39.github.io/ecma262/#sec-proxy.revocable
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/revocable
+ */
+Proxy.revocable = function(target, handler) {};
diff --git a/javascript/externs/web/fido.js b/javascript/externs/web/fido.js
new file mode 100644
index 000000000000..98c75317ea2f
--- /dev/null
+++ b/javascript/externs/web/fido.js
@@ -0,0 +1,94 @@
+/*
+ * Copyright 2018 The Closure Compiler Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions from the FIDO Specifications
+ * @see https://fidoalliance.org/download/
+ *
+ * @externs
+ * @author arnarbi@gmail.com (Arnar Birgisson)
+ */
+
+/**
+ * U2F JavaScript API namespace
+ * @see https://fidoalliance.org/specs/fido-u2f-v1.2-ps-20170411/fido-u2f-javascript-api-v1.2-ps-20170411.html
+ * @const
+ */
+var u2f = {};
+
+/**
+ * Data object for a single sign request.
+ * @typedef {string}
+ */
+u2f.Transport;
+
+/**
+ * Data object for a registered key.
+ * @typedef {{
+ *   version: string,
+ *   keyHandle: string,
+ *   transports: (!Array<!u2f.Transport>|undefined),
+ *   appId: ?string
+ * }}
+ */
+u2f.RegisteredKey;
+
+/**
+ * An error object for responses
+ * @typedef {{
+ *   errorCode: number,
+ *   errorMessage: ?string
+ * }}
+ */
+u2f.Error;
+
+/**
+ * Data object for a sign response.
+ * @typedef {{
+ *   keyHandle: string,
+ *   signatureData: string,
+ *   clientData: string
+ * }}
+ */
+u2f.SignResponse;
+
+/**
+ * @typedef {{
+ *   version: string,
+ *   challenge: string
+ * }}
+ */
+u2f.RegisterRequest
+
+/**
+ * @param {string} appId
+ * @param {string} challenge
+ * @param {!Array<!u2f.RegisteredKey>} registeredKeys
+ * @param {function((!u2f.Error|!u2f.SignResponse))} callback
+ * @param {number=} opt_timeoutSeconds
+ */
+u2f.sign = function(
+    appId, challenge, registeredKeys, callback, opt_timeoutSeconds) {};
+
+/**
+ * @param {string} appId
+ * @param {!Array<!u2f.RegisterRequest>} registerRequests
+ * @param {!Array<!u2f.RegisteredKey>} registeredKeys
+ * @param {function((!u2f.Error|!u2f.SignResponse))} callback
+ * @param {number=} opt_timeoutSeconds
+ */
+u2f.register = function(
+    appId, registerRequests, registeredKeys, callback, opt_timeoutSeconds) {};
diff --git a/javascript/externs/web/google_legacy.js b/javascript/externs/web/google_legacy.js
new file mode 100644
index 000000000000..c8851d276897
--- /dev/null
+++ b/javascript/externs/web/google_legacy.js
@@ -0,0 +1,31 @@
+/*
+ * Copyright 2010 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Declaration of the type level google namespace.
+ * @externs
+ * @author nicksantos@google.com (Nick Santos)
+ */
+
+/**
+ * Suppresses the compiler warning when multiple externs files declare the
+ * google namespace.
+ * @suppress {duplicate,strictMissingProperties}
+ * NOTE: This definition should be marked \@const, and when it is we can remove
+ * the "strictMissingProperties" suppression.
+ */
+// TODO(nicksantos): Consolidate to one google namespace declaration.
+var google = {};
diff --git a/javascript/externs/web/intersection_observer.js b/javascript/externs/web/intersection_observer.js
new file mode 100644
index 000000000000..0dd991fcf4f1
--- /dev/null
+++ b/javascript/externs/web/intersection_observer.js
@@ -0,0 +1,178 @@
+/*
+ * Copyright 2016 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Externs for Intersection Observer objects.
+ * @see https://w3c.github.io/IntersectionObserver/
+ * @externs
+ */
+
+// TODO(user): Once the Intersection Observer spec is adopted by W3C, add
+// a w3c_ prefix to this file's name.
+
+
+/**
+ * These contain the information provided from a change event.
+ * @see https://w3c.github.io/IntersectionObserver/#intersection-observer-entry
+ * @record
+ */
+function IntersectionObserverEntry() {}
+
+/**
+ * The time the change was observed.
+ * @see https://w3c.github.io/IntersectionObserver/#dom-intersectionobserverentry-time
+ * @const {number}
+ */
+IntersectionObserverEntry.prototype.time;
+
+/**
+ * The root intersection rectangle, if target belongs to the same unit of
+ * related similar-origin browsing contexts as the intersection root, null
+ * otherwise.
+ * @see https://w3c.github.io/IntersectionObserver/#dom-intersectionobserverentry-rootbounds
+ * @const {{top: number, right: number, bottom: number, left: number,
+ *     height: number, width: number}}
+ */
+IntersectionObserverEntry.prototype.rootBounds;
+
+/**
+ * The rectangle describing the element being observed.
+ * @see https://w3c.github.io/IntersectionObserver/#dom-intersectionobserverentry-boundingclientrect
+ * @const {!{top: number, right: number, bottom: number, left: number,
+ *     height: number, width: number}}
+ */
+IntersectionObserverEntry.prototype.boundingClientRect;
+
+/**
+ * The rectangle describing the intersection between the observed element and
+ * the viewport.
+ * @see https://w3c.github.io/IntersectionObserver/#dom-intersectionobserverentry-intersectionrect
+ * @const {!{top: number, right: number, bottom: number, left: number,
+ *     height: number, width: number}}
+ */
+IntersectionObserverEntry.prototype.intersectionRect;
+
+/**
+ * Ratio of intersectionRect area to boundingClientRect area.
+ * @see https://w3c.github.io/IntersectionObserver/#dom-intersectionobserverentry-intersectionratio
+ * @const {number}
+ */
+IntersectionObserverEntry.prototype.intersectionRatio;
+
+/**
+ * The Element whose intersection with the intersection root changed.
+ * @see https://w3c.github.io/IntersectionObserver/#dom-intersectionobserverentry-target
+ * @const {!Element}
+ */
+IntersectionObserverEntry.prototype.target;
+
+/**
+ * Whether or not the target is intersecting with the root.
+ * @see https://w3c.github.io/IntersectionObserver/#dom-intersectionobserverentry-isintersecting
+ * @const {boolean}
+ */
+IntersectionObserverEntry.prototype.isIntersecting;
+
+/**
+ * Whether or not the target is visible with the root.
+ * @see https://w3c.github.io/IntersectionObserver/v2/#dom-intersectionobserverentry-isvisible
+ * @const {boolean|undefined}
+ */
+IntersectionObserverEntry.prototype.isVisible;
+
+/**
+ * Callback for the IntersectionObserver.
+ * @see https://w3c.github.io/IntersectionObserver/#intersection-observer-callback
+ * @typedef {function(!Array<!IntersectionObserverEntry>,!IntersectionObserver)}
+ */
+var IntersectionObserverCallback;
+
+/**
+ * Options for the IntersectionObserver.
+ * @see https://w3c.github.io/IntersectionObserver/v2/#intersection-observer-init
+ * @typedef {{
+ *   threshold: (!Array<number>|number|undefined),
+ *   delay: (number|undefined),
+ *   trackVisibility: (boolean|undefined),
+ *   root: (?Element|undefined),
+ *   rootMargin: (string|undefined)
+ * }}
+ */
+var IntersectionObserverInit;
+
+/**
+ * This is the constructor for Intersection Observer objects.
+ * @see https://w3c.github.io/IntersectionObserver/#intersection-observer-interface
+ * @param {!IntersectionObserverCallback} handler The callback for the observer.
+ * @param {!IntersectionObserverInit=} opt_options The object defining the
+ *     thresholds, etc.
+ * @constructor
+ */
+function IntersectionObserver(handler, opt_options) {};
+
+/**
+ * The root Element to use for intersection, or null if the observer uses the
+ * implicit root.
+ * @see https://w3c.github.io/IntersectionObserver/#dom-intersectionobserver-root
+ * @const {?Element}
+ */
+IntersectionObserver.prototype.root;
+
+/**
+ * Offsets applied to the intersection root’s bounding box, effectively growing
+ * or shrinking the box that is used to calculate intersections.
+ * @see https://w3c.github.io/IntersectionObserver/#dom-intersectionobserver-rootmargin
+ * @const {string}
+ */
+IntersectionObserver.prototype.rootMargin;
+
+/**
+ * A list of thresholds, sorted in increasing numeric order, where each
+ * threshold is a ratio of intersection area to bounding box area of an observed
+ * target.
+ * @see https://w3c.github.io/IntersectionObserver/#dom-intersectionobserver-thresholds
+ * @const {!Array<number>}
+ */
+IntersectionObserver.prototype.thresholds;
+
+/**
+ * This is used to set which element to observe.
+ * @see https://w3c.github.io/IntersectionObserver/#dom-intersectionobserver-observe
+ * @param {!Element} element The element to observe.
+ * @return {undefined}
+ */
+IntersectionObserver.prototype.observe = function(element) {};
+
+/**
+ * This is used to stop observing a given element.
+ * @see https://w3c.github.io/IntersectionObserver/#dom-intersectionobserver-unobserve
+ * @param {!Element} element The elmenent to stop observing.
+ * @return {undefined}
+ */
+IntersectionObserver.prototype.unobserve = function(element) {};
+
+/**
+ * Disconnect.
+ * @see https://w3c.github.io/IntersectionObserver/#dom-intersectionobserver-disconnect
+ */
+IntersectionObserver.prototype.disconnect = function() {};
+
+/**
+ * Take records.
+ * @see https://w3c.github.io/IntersectionObserver/#dom-intersectionobserver-takerecords
+ * @return {!Array.<!IntersectionObserverEntry>}
+ */
+IntersectionObserver.prototype.takeRecords = function() {};
diff --git a/javascript/externs/web/mediakeys.js b/javascript/externs/web/mediakeys.js
new file mode 100644
index 000000000000..e6230288fc17
--- /dev/null
+++ b/javascript/externs/web/mediakeys.js
@@ -0,0 +1,305 @@
+/*
+ * Copyright 2015 The Closure Compiler authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/**
+ * @fileoverview MediaKey externs.
+ * Based on {@link https://w3c.github.io/encrypted-media/ EME draft 5 December
+ * 2019}.
+ * @externs
+ */
+
+
+/**
+ * @typedef {{
+ *   contentType: string,
+ *   encryptionScheme: (?string|undefined),
+ *   robustness: (string|undefined)
+ * }}
+ * @see https://w3c.github.io/encrypted-media/#mediakeysystemmediacapability-dictionary
+ */
+var MediaKeySystemMediaCapability;
+
+
+/** @typedef {{
+ *   label: (string|undefined),
+ *   initDataTypes: (!Array<string>|undefined),
+ *   audioCapabilities: (!Array<!MediaKeySystemMediaCapability>|undefined),
+ *   videoCapabilities: (!Array<!MediaKeySystemMediaCapability>|undefined),
+ *   distinctiveIdentifier: (string|undefined),
+ *   persistentState: (string|undefined),
+ *   sessionTypes: (!Array<string>|undefined)
+ * }}
+ * @see https://w3c.github.io/encrypted-media/#mediakeysystemconfiguration-dictionary
+ */
+var MediaKeySystemConfiguration;
+
+
+/**
+ * @param {string} keySystem
+ * @param {!Array<!MediaKeySystemConfiguration>} supportedConfigurations
+ * @return {!Promise<!MediaKeySystemAccess>}
+ * @see https://w3c.github.io/encrypted-media/#navigator-extension-requestmediakeysystemaccess
+ */
+Navigator.prototype.requestMediaKeySystemAccess =
+    function(keySystem, supportedConfigurations) {};
+
+
+/** @const {MediaKeys} */
+HTMLMediaElement.prototype.mediaKeys;
+
+
+/**
+ * @param {MediaKeys} mediaKeys
+ * @return {!Promise}
+ * @see https://w3c.github.io/encrypted-media/#dom-htmlmediaelement-setmediakeys
+ */
+HTMLMediaElement.prototype.setMediaKeys = function(mediaKeys) {};
+
+
+
+/**
+ * @interface
+ * @see https://w3c.github.io/encrypted-media/#mediakeysystemaccess-interface
+ */
+function MediaKeySystemAccess() {}
+
+
+/** @return {!Promise<!MediaKeys>} */
+MediaKeySystemAccess.prototype.createMediaKeys = function() {};
+
+
+/** @return {!MediaKeySystemConfiguration} */
+MediaKeySystemAccess.prototype.getConfiguration = function() {};
+
+
+/** @const {string} */
+MediaKeySystemAccess.prototype.keySystem;
+
+
+
+/**
+ * @interface
+ * @see https://w3c.github.io/encrypted-media/#mediakeys-interface
+ */
+function MediaKeys() {}
+
+
+/**
+ * @param {string=} opt_sessionType defaults to "temporary"
+ * @return {!MediaKeySession}
+ * @throws {TypeError} if opt_sessionType is invalid.
+ */
+MediaKeys.prototype.createSession = function(opt_sessionType) {};
+
+
+/**
+ * @param {!BufferSource} serverCertificate
+ * @return {!Promise}
+ */
+MediaKeys.prototype.setServerCertificate = function(serverCertificate) {};
+
+
+
+/**
+ * @interface
+ * @see https://w3c.github.io/encrypted-media/#mediakeystatusmap-interface
+ */
+function MediaKeyStatusMap() {}
+
+
+/** @const {number} */
+MediaKeyStatusMap.prototype.size;
+
+
+/**
+ * Array entry 0 is the key, 1 is the value.
+ * @return {!Iterator<!Array<!BufferSource|string>>}
+ */
+MediaKeyStatusMap.prototype.entries = function() {};
+
+
+/**
+ * The function is called with each value.
+ * @param {function(string, !BufferSource)} callback A callback function to run for
+ *     each media key. The first parameter is the key status; the second
+ *     parameter is the key ID.
+ * @return {undefined}
+ */
+MediaKeyStatusMap.prototype.forEach = function(callback) {};
+
+
+/**
+ * @param {!BufferSource} keyId
+ * @return {string|undefined}
+ */
+MediaKeyStatusMap.prototype.get = function(keyId) {};
+
+
+/**
+ * @param {!BufferSource} keyId
+ * @return {boolean}
+ */
+MediaKeyStatusMap.prototype.has = function(keyId) {};
+
+
+/**
+ * @return {!Iterator<!BufferSource>}
+ */
+MediaKeyStatusMap.prototype.keys = function() {};
+
+
+/**
+ * @return {!Iterator<string>}
+ */
+MediaKeyStatusMap.prototype.values = function() {};
+
+
+
+/**
+ * @interface
+ * @extends {EventTarget}
+ * @see https://w3c.github.io/encrypted-media/#mediakeysession-interface
+ */
+function MediaKeySession() {}
+
+
+/** @const {string} */
+MediaKeySession.prototype.sessionId;
+
+
+/** @const {number} */
+MediaKeySession.prototype.expiration;
+
+
+/** @const {!Promise} */
+MediaKeySession.prototype.closed;
+
+
+/** @const {!MediaKeyStatusMap} */
+MediaKeySession.prototype.keyStatuses;
+
+
+/**
+ * @param {string} initDataType
+ * @param {!BufferSource} initData
+ * @return {!Promise}
+ */
+MediaKeySession.prototype.generateRequest = function(initDataType, initData) {};
+
+
+/**
+ * @param {string} sessionId
+ * @return {!Promise<boolean>}}
+ */
+MediaKeySession.prototype.load = function(sessionId) {};
+
+
+/**
+ * @param {!BufferSource} response
+ * @return {!Promise}
+ */
+MediaKeySession.prototype.update = function(response) {};
+
+
+/** @return {!Promise} */
+MediaKeySession.prototype.close = function() {};
+
+
+/** @return {!Promise} */
+MediaKeySession.prototype.remove = function() {};
+
+
+/** @override */
+MediaKeySession.prototype.addEventListener = function(
+    type, listener, opt_options) {};
+
+
+/** @override */
+MediaKeySession.prototype.removeEventListener = function(
+    type, listener, opt_options) {};
+
+
+/** @override */
+MediaKeySession.prototype.dispatchEvent = function(evt) {};
+
+/**
+ * @record
+ * @extends {EventInit}
+ * @see https://w3c.github.io/encrypted-media/#dom-mediakeymessageeventinit
+ */
+function MediaKeyMessageEventInit() {};
+
+/** @type {string} */
+MediaKeyMessageEventInit.prototype.messageType;
+
+/** @type {!ArrayBuffer} */
+MediaKeyMessageEventInit.prototype.message;
+
+
+/**
+ * @constructor
+ * @param {string} type
+ * @param {MediaKeyMessageEventInit} eventInitDict
+ * @extends {Event}
+ * @see https://w3c.github.io/encrypted-media/#mediakeymessageevent
+ */
+function MediaKeyMessageEvent(type, eventInitDict) {}
+
+
+/** @const {string} */
+MediaKeyMessageEvent.prototype.messageType;
+
+
+/** @const {!ArrayBuffer} */
+MediaKeyMessageEvent.prototype.message;
+
+
+/** @const {!MediaKeySession} */
+MediaKeyMessageEvent.prototype.target;
+
+/**
+ * @record
+ * @extends {EventInit}
+ * @see https://w3c.github.io/encrypted-media/#dom-mediaencryptedeventinit
+ */
+function MediaEncryptedEventInit() {};
+
+/** @type {(string | undefined)} */
+MediaEncryptedEventInit.prototype.initDataType;
+
+/** @type {(ArrayBuffer | undefined)} */
+MediaEncryptedEventInit.prototype.initData;
+
+/**
+ * @constructor
+ * @param {string} type
+ * @param {MediaEncryptedEventInit=} opt_eventInitDict
+ * @extends {Event}
+ * @see https://w3c.github.io/encrypted-media/#mediaencryptedevent
+ */
+function MediaEncryptedEvent(type, opt_eventInitDict) {}
+
+
+/** @const {string} */
+MediaEncryptedEvent.prototype.initDataType;
+
+
+/** @const {ArrayBuffer} */
+MediaEncryptedEvent.prototype.initData;
+
+
+/** @const {!HTMLMediaElement} */
+MediaEncryptedEvent.prototype.target;
+
diff --git a/javascript/externs/web/nonstandard_anim_timing.js b/javascript/externs/web/nonstandard_anim_timing.js
new file mode 100644
index 000000000000..b1683ec31bce
--- /dev/null
+++ b/javascript/externs/web/nonstandard_anim_timing.js
@@ -0,0 +1,97 @@
+/*
+ * Copyright 2011 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/**
+ * @fileoverview Nonstandard definitions for timing control for script base animations.
+ *
+ * @externs
+ */
+
+/**
+ * @param {!FrameRequestCallback} callback
+ * @param {Element=} opt_element
+ * @return {number}
+ */
+function webkitRequestAnimationFrame(callback, opt_element) {};
+
+/**
+ * @param {number} handle
+ * @return {undefined}
+ */
+function webkitCancelRequestAnimationFrame(handle) {};
+
+/**
+ * @param {number} handle
+ * @return {undefined}
+ */
+function webkitCancelAnimationFrame(handle) {};
+
+/**
+ * @param {?FrameRequestCallback} callback It's legitimate to pass a null
+ *     callback and listen on the MozBeforePaint event instead.
+ * @param {Element=} opt_element
+ * @return {number}
+ */
+function mozRequestAnimationFrame(callback, opt_element) {};
+
+/**
+ * @param {number} handle
+ * @return {undefined}
+ */
+function mozCancelRequestAnimationFrame(handle) {};
+
+/**
+ * @param {number} handle
+ * @return {undefined}
+ */
+function mozCancelAnimationFrame(handle) {};
+
+/**
+ * @param {!FrameRequestCallback} callback
+ * @param {Element=} opt_element
+ * @return {number}
+ */
+function msRequestAnimationFrame(callback, opt_element) {};
+
+/**
+ * @param {number} handle
+ * @return {undefined}
+ */
+function msCancelRequestAnimationFrame(handle) {};
+
+/**
+ * @param {number} handle
+ * @return {undefined}
+ */
+function msCancelAnimationFrame(handle) {};
+
+/**
+ * @param {!FrameRequestCallback} callback
+ * @param {Element=} opt_element
+ * @return {number}
+ */
+function oRequestAnimationFrame(callback, opt_element) {};
+
+/**
+ * @param {number} handle
+ * @return {undefined}
+ */
+function oCancelRequestAnimationFrame(handle) {};
+
+/**
+ * @param {number} handle
+ * @return {undefined}
+ */
+function oCancelAnimationFrame(handle) {};
diff --git a/javascript/externs/web/nonstandard_audio.js b/javascript/externs/web/nonstandard_audio.js
new file mode 100644
index 000000000000..ee175bf8df34
--- /dev/null
+++ b/javascript/externs/web/nonstandard_audio.js
@@ -0,0 +1,82 @@
+/*
+ * Copyright 2012 The Closure Compiler Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Nonstandard definitions for the API related to audio.
+ *
+ * @externs
+ */
+
+/**
+ * Definitions for the Web Audio API with webkit prefix.
+ */
+
+/**
+ * @constructor
+ * @extends {AudioContext}
+ */
+function webkitAudioContext() {}
+
+/**
+ * @param {number} numberOfChannels
+ * @param {number} length
+ * @param {number} sampleRate
+ * @constructor
+ * @extends {OfflineAudioContext}
+ */
+function webkitOfflineAudioContext(numberOfChannels, length, sampleRate) {}
+
+/**
+ * @constructor
+ * @extends {AudioPannerNode}
+ */
+function webkitAudioPannerNode() {}
+
+/**
+ * @constructor
+ * @extends {PannerNode}
+ */
+function webkitPannerNode() {}
+
+/**
+ * Definitions for the Audio API as implemented in Firefox.
+ *   Please note that this document describes a non-standard experimental API.
+ *   This API is considered deprecated.
+ * @see https://developer.mozilla.org/en/DOM/HTMLAudioElement
+ */
+
+/**
+ * @param {string=} src
+ * @constructor
+ * @extends {HTMLAudioElement}
+ */
+function Audio(src) {}
+
+/**
+ * @param {number} channels
+ * @param {number} rate
+ */
+Audio.prototype.mozSetup = function(channels, rate) {};
+
+/**
+ * @param {Array|Float32Array} buffer
+ */
+Audio.prototype.mozWriteAudio = function(buffer) {};
+
+/**
+ * @return {number}
+ */
+Audio.prototype.mozCurrentSampleOffset = function() {};
diff --git a/javascript/externs/web/nonstandard_console.js b/javascript/externs/web/nonstandard_console.js
new file mode 100644
index 000000000000..b6c1af55277f
--- /dev/null
+++ b/javascript/externs/web/nonstandard_console.js
@@ -0,0 +1,66 @@
+/*
+ * Copyright 2019 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for console debugging facilities implemented in
+ *     various browsers but not part of https://console.spec.whatwg.org/.
+ * @externs
+ */
+
+/**
+ * @constructor
+ * @see https://cs.chromium.org/search/?q=%22interface+MemoryInfo%22+file:idl+file:WebKit+package:chromium&type=cs
+ */
+function MemoryInfo() {};
+
+/** @type {number} */
+MemoryInfo.prototype.totalJSHeapSize;
+
+/** @type {number} */
+MemoryInfo.prototype.usedJSHeapSize;
+
+/** @type {number} */
+MemoryInfo.prototype.jsHeapSizeLimit;
+
+/**
+ * @param {*} value
+ * @return {undefined}
+ */
+Console.prototype.markTimeline = function(value) {};
+
+/**
+ * @param {string=} title
+ * @return {undefined}
+ */
+Console.prototype.profile = function(title) {};
+
+/** @type {Array<ScriptProfile>} */
+Console.prototype.profiles;
+
+/**
+ * @param {string=} title
+ * @return {undefined}
+ */
+Console.prototype.profileEnd = function(title) {};
+
+/**
+ * @param {*} value
+ * @return {undefined}
+ */
+Console.prototype.timeStamp = function(value) {};
+
+/** @type {MemoryInfo} */
+Console.prototype.memory;
diff --git a/javascript/externs/web/nonstandard_indexeddb.js b/javascript/externs/web/nonstandard_indexeddb.js
new file mode 100644
index 000000000000..b7334b6e6540
--- /dev/null
+++ b/javascript/externs/web/nonstandard_indexeddb.js
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2011 The Closure Compiler Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Browser specific definitions for W3C's IndexedDB API
+ * @externs
+ */
+
+/** @type {!IDBFactory|undefined} */
+Window.prototype.moz_indexedDB;
+
+/** @type {!IDBFactory|undefined} */
+Window.prototype.mozIndexedDB;
+
+/** @type {!IDBFactory|undefined} */
+Window.prototype.webkitIndexedDB;
+
+/** @type {!IDBFactory|undefined} */
+Window.prototype.msIndexedDB;
+
+/**
+ * @constructor
+ * @extends {IDBRequest}
+ * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBRequest
+ * @see https://www.w3.org/TR/IndexedDB-2/#request-api
+ */
+function webkitIDBRequest() {}
+
+/**
+ * @constructor
+ * @extends {IDBCursor}
+ * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBCursor
+ * @see https://www.w3.org/TR/IndexedDB-2/#cursor-interface
+ */
+function webkitIDBCursor() {}
+
+/**
+ * @constructor
+ * @extends {IDBTransaction}
+ * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBTransaction
+ * @see https://www.w3.org/TR/IndexedDB-2/#transaction
+ */
+function webkitIDBTransaction() {}
+
+/**
+ * @constructor
+ * @extends {IDBKeyRange}
+ * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBKeyRange
+ * @see https://www.w3.org/TR/IndexedDB-2/#keyrange
+ */
+function webkitIDBKeyRange() {}
+
+/**
+ * @param {string} type
+ * @param {!IDBVersionChangeEventInit=} eventInit
+ * @constructor
+ * @extends {IDBVersionChangeEvent}
+ * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBVersionChangeEvent
+ */
+function webkitIDBVersionChangeEvent(type, eventInit) {}
+
+/**
+ * @const {string}
+ */
+webkitIDBVersionChangeEvent.prototype.version;
diff --git a/javascript/externs/web/nonstandard_navigation_timing.js b/javascript/externs/web/nonstandard_navigation_timing.js
new file mode 100644
index 000000000000..fa2c8b58e764
--- /dev/null
+++ b/javascript/externs/web/nonstandard_navigation_timing.js
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2011 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Nonstandard Definitions for W3C's Navigation Timing
+ * specification.
+ *
+ * @externs
+ */
+
+// Nonstandard. Only available in Blink.
+// Returns more granular results with the --enable-memory-info flag.
+/** @type {MemoryInfo} */ Performance.prototype.memory;
+
+/**
+ * Clear out the buffer of performance timing events for webkit browsers.
+ * @return {undefined}
+ */
+Performance.prototype.webkitClearResourceTimings = function() {};
+
+/**
+ * @return {number}
+ * @nosideeffects
+ */
+Performance.prototype.webkitNow = function() {};
diff --git a/javascript/externs/web/nonstandard_rtc.js b/javascript/externs/web/nonstandard_rtc.js
new file mode 100644
index 000000000000..a9c5f5ae6158
--- /dev/null
+++ b/javascript/externs/web/nonstandard_rtc.js
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2019 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Nonstandard definitions for components of the WebRTC browser
+ * API.
+ *
+ * @externs
+ */
+
+/**
+ * @type {function(new: MediaStream,
+ *                 (!MediaStream|!Array<!MediaStreamTrack>)=)}
+ */
+var webkitMediaStream;
+
+/**
+ * @param {MediaStreamConstraints} constraints A MediaStreamConstraints object.
+ * @param {function(!MediaStream)} successCallback
+ *     A NavigatorUserMediaSuccessCallback function.
+ * @param {function(!NavigatorUserMediaError)=} errorCallback A
+ *     NavigatorUserMediaErrorCallback function.
+ * @see http://dev.w3.org/2011/webrtc/editor/getusermedia.html
+ * @see https://www.w3.org/TR/mediacapture-streams/
+ * @return {undefined}
+ */
+Navigator.prototype.webkitGetUserMedia = function(
+    constraints, successCallback, errorCallback) {};
+
+/** @const */
+var webkitRTCPeerConnection = RTCPeerConnection;
diff --git a/javascript/externs/web/nonstandard_selection.js b/javascript/externs/web/nonstandard_selection.js
new file mode 100644
index 000000000000..248f5dd9a5eb
--- /dev/null
+++ b/javascript/externs/web/nonstandard_selection.js
@@ -0,0 +1,80 @@
+/*
+ * Copyright 2011 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Nonstandard enhancements to W3C's Selection API.
+ *
+ * @externs
+ */
+
+// The following were sources from the webkit externs.
+
+/** @type {?Node} */
+Selection.prototype.baseNode;
+
+/** @type {number} */
+Selection.prototype.baseOffset;
+
+/** @type {?Node} */
+Selection.prototype.extentNode;
+
+/** @type {number} */
+Selection.prototype.extentOffset;
+
+/**
+ * @param {string} alter
+ * @param {string} direction
+ * @param {string} granularity
+ * @return {undefined}
+ */
+Selection.prototype.modify = function(alter, direction, granularity) {};
+
+
+// The following were sources from the gecko externs.
+
+
+/**
+ * @see https://developer.mozilla.org/en/DOM/Selection/selectionLanguageChange
+ */
+Selection.prototype.selectionLanguageChange;
+
+
+// The following were sources from the ie externs.
+
+
+/**
+ * @type {?Selection}
+ * @see http://msdn.microsoft.com/en-us/library/ms535869(VS.85).aspx
+ */
+Document.prototype.selection;
+
+/**
+ * @return {undefined}
+ * @see http://msdn.microsoft.com/en-us/library/ms536418(VS.85).aspx
+ */
+Selection.prototype.clear = function() {};
+
+/**
+ * @return {?TextRange|?ControlRange}
+ * @see http://msdn.microsoft.com/en-us/library/ms536394(VS.85).aspx
+ */
+Selection.prototype.createRange = function() {};
+
+/**
+ * @return {?Array<?TextRange>}
+ * @see http://msdn.microsoft.com/en-us/library/ms536396(VS.85).aspx
+ */
+Selection.prototype.createRangeCollection = function() {};
diff --git a/javascript/externs/web/w3c_abort.js b/javascript/externs/web/w3c_abort.js
new file mode 100644
index 000000000000..cd023450ca5d
--- /dev/null
+++ b/javascript/externs/web/w3c_abort.js
@@ -0,0 +1,50 @@
+/*
+ * Copyright 2018 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for AbortController
+ * @see https://dom.spec.whatwg.org/#aborting-ongoing-activities
+ * @externs
+ */
+
+
+
+/**
+ * @record
+ * @extends {EventTarget}
+ * @see https://dom.spec.whatwg.org/#interface-AbortSignal
+ */
+function AbortSignal() {}
+
+/** @type {boolean} */
+AbortSignal.prototype.aborted;
+
+/** @type {?function(!Event)} */
+AbortSignal.prototype.onabort;
+
+
+
+/**
+ * @constructor
+ * @see https://dom.spec.whatwg.org/#interface-abortcontroller
+ */
+function AbortController() {}
+
+/** @const {!AbortSignal} */
+AbortController.prototype.signal;
+
+/** @return {void} */
+AbortController.prototype.abort = function() {};
diff --git a/javascript/externs/web/w3c_audio.js b/javascript/externs/web/w3c_audio.js
new file mode 100644
index 000000000000..4a8729846cc0
--- /dev/null
+++ b/javascript/externs/web/w3c_audio.js
@@ -0,0 +1,1587 @@
+/*
+ * Copyright 2012 The Closure Compiler Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for the API related to audio.
+ * Definitions for the Web Audio API.
+ * This file is based on the W3C Working Draft 08 December 2015.
+ * @see http://www.w3.org/TR/webaudio/
+ *
+ * @externs
+ */
+
+/**
+ * @implements {EventTarget}
+ * @constructor
+ */
+function BaseAudioContext() {}
+
+/** @type {!AudioDestinationNode} */
+BaseAudioContext.prototype.destination;
+
+/** @type {number} */
+BaseAudioContext.prototype.sampleRate;
+
+/** @type {number} */
+BaseAudioContext.prototype.currentTime;
+
+/** @type {!AudioListener} */
+BaseAudioContext.prototype.listener;
+
+/** @type {!AudioWorklet} */
+BaseAudioContext.prototype.audioWorklet;
+
+/**
+ * @type {string}
+ * See https://www.w3.org/TR/webaudio/#BaseAudioContext for valid values
+ */
+BaseAudioContext.prototype.state;
+
+/**
+ * @param {number} numberOfChannels
+ * @param {number} length
+ * @param {number} sampleRate
+ * @return {!AudioBuffer}
+ */
+BaseAudioContext.prototype.createBuffer =
+    function(numberOfChannels, length, sampleRate) {};
+
+/**
+ * @param {!ArrayBuffer} audioData
+ * @param {function(!AudioBuffer)=} successCallback
+ * @param {function(?)=} errorCallback
+ * @return {!Promise<!AudioBuffer>}
+ */
+BaseAudioContext.prototype.decodeAudioData =
+    function(audioData, successCallback, errorCallback) {};
+
+/**
+ * @return {!AudioBufferSourceNode}
+ */
+BaseAudioContext.prototype.createBufferSource = function() {};
+
+/**
+ * @deprecated Use createAudioWorker instead
+ * @param {number=} bufferSize
+ * @param {number=} numberOfInputChannels_opt
+ * @param {number=} numberOfOutputChannels_opt
+ * @return {!ScriptProcessorNode}
+ */
+BaseAudioContext.prototype.createScriptProcessor = function(bufferSize,
+    numberOfInputChannels_opt, numberOfOutputChannels_opt) {};
+
+/**
+ * @return {!AnalyserNode}
+ */
+BaseAudioContext.prototype.createAnalyser = function() {};
+
+/**
+ * @return {!GainNode}
+ */
+BaseAudioContext.prototype.createGain = function() {};
+
+/**
+ * @param {number=} maxDelayTime
+ * @return {!DelayNode}
+ */
+BaseAudioContext.prototype.createDelay = function(maxDelayTime) {};
+
+/**
+ * @return {!BiquadFilterNode}
+ */
+BaseAudioContext.prototype.createBiquadFilter = function() {};
+
+/**
+ * @return {!WaveShaperNode}
+ */
+BaseAudioContext.prototype.createWaveShaper = function() {};
+
+/**
+ * @return {!PannerNode}
+ */
+BaseAudioContext.prototype.createPanner = function() {};
+
+/**
+ * @return {!StereoPannerNode}
+ */
+BaseAudioContext.prototype.createStereoPanner = function() {};
+
+/**
+ * @return {!ConvolverNode}
+ */
+BaseAudioContext.prototype.createConvolver = function() {};
+
+/**
+ * @param {number=} numberOfOutputs
+ * @return {!ChannelSplitterNode}
+ */
+BaseAudioContext.prototype.createChannelSplitter = function(numberOfOutputs) {};
+
+/**
+ * @param {number=} numberOfInputs
+ * @return {!ChannelMergerNode}
+ */
+BaseAudioContext.prototype.createChannelMerger = function(numberOfInputs) {};
+
+/**
+ * @return {!ConstantSourceNode}
+ */
+BaseAudioContext.prototype.createConstantSource = function() {};
+
+/**
+ * @return {!DynamicsCompressorNode}
+ */
+BaseAudioContext.prototype.createDynamicsCompressor = function() {};
+
+/**
+ * @return {!OscillatorNode}
+ */
+BaseAudioContext.prototype.createOscillator = function() {};
+
+/**
+ * @param {!Float32Array} real
+ * @param {!Float32Array} imag
+ * @return {!PeriodicWave}
+ */
+BaseAudioContext.prototype.createPeriodicWave = function(real, imag) {};
+
+/**
+ * @return {!Promise<void>}
+ */
+BaseAudioContext.prototype.resume = function() {};
+
+/**
+ * @return {!Promise<void>}
+ */
+BaseAudioContext.prototype.suspend = function() {};
+
+/**
+ * @return {!Promise<void>}
+ */
+BaseAudioContext.prototype.close = function() {};
+
+/** @type {?function(!Event)} */
+BaseAudioContext.prototype.onstatechange;
+
+/**
+ * @param  {string} scriptURL
+ * @return {!Promise<!AudioWorker>}
+ */
+BaseAudioContext.prototype.createAudioWorker = function(scriptURL) {};
+
+/**
+ * @param  {!IArrayLike<number>} feedforward
+ * @param  {!IArrayLike<number>} feedback
+ * @return {!IIRFilterNode}
+ */
+BaseAudioContext.prototype.createIIRFilter = function(feedforward, feedback) {};
+
+/**
+ * @return {!SpatialPannerNode}
+ */
+BaseAudioContext.prototype.createSpatialPanner = function() {};
+
+/**
+ * @record
+ * @see https://webaudio.github.io/web-audio-api/#idl-def-AudioContextOptions
+ */
+function AudioContextOptions() {};
+
+/** @type {(undefined|string|number)} */
+AudioContextOptions.prototype.latencyHint;
+
+/** @type {(undefined|number)} */
+AudioContextOptions.prototype.sampleRate;
+
+/**
+ * Includes the non-standard contextOptions optional options parameter
+ * implemented by Chrome and Firefox.
+ * @param {!AudioContextOptions=} contextOptions
+ * @constructor
+ * @extends {BaseAudioContext}
+ */
+function AudioContext(contextOptions) {}
+
+/**
+ * @param {!HTMLMediaElement} mediaElement
+ * @return {!MediaElementAudioSourceNode}
+ */
+AudioContext.prototype.createMediaElementSource = function(mediaElement) {};
+
+/**
+ * @return {!MediaStreamAudioDestinationNode}
+ */
+AudioContext.prototype.createMediaStreamDestination = function() {};
+
+/**
+ * @param {!MediaStream} mediaStream
+ * @return {!MediaStreamAudioSourceNode}
+ */
+AudioContext.prototype.createMediaStreamSource = function(mediaStream) {};
+
+/**
+ * @deprecated Use createScriptProcessor instead.
+ * @param {number} bufferSize
+ * @param {number} numberOfInputs
+ * @param {number} numberOfOuputs
+ * @return {!ScriptProcessorNode}
+ */
+AudioContext.prototype.createJavaScriptNode = function(bufferSize,
+    numberOfInputs, numberOfOuputs) {};
+
+/**
+ * @deprecated Use createGain instead.
+ * @return {!GainNode}
+ */
+AudioContext.prototype.createGainNode = function() {};
+
+/**
+ * @deprecated Use createDelay instead.
+ * @param {number=} maxDelayTime
+ * @return {!DelayNode}
+ */
+AudioContext.prototype.createDelayNode = function(maxDelayTime) {};
+
+/**
+ * @param {number} numberOfChannels
+ * @param {number} length
+ * @param {number} sampleRate
+ * @constructor
+ * @extends {BaseAudioContext}
+ */
+function OfflineAudioContext(numberOfChannels, length, sampleRate) {}
+
+/**
+ * @return {!Promise<!AudioBuffer>}
+ */
+OfflineAudioContext.prototype.startRendering = function() {};
+
+/** @type {function(!OfflineAudioCompletionEvent)} */
+OfflineAudioContext.prototype.oncomplete;
+
+/**
+ * @constructor
+ * @extends {Event}
+ */
+function OfflineAudioCompletionEvent() {}
+
+/** @type {AudioBuffer} */
+OfflineAudioCompletionEvent.prototype.renderedBuffer;
+
+/**
+ * @constructor
+ * @implements {EventTarget}
+ * @see https://www.w3.org/TR/webaudio/#the-audionode-interface
+ */
+function AudioNode() {}
+
+/**
+ * @override
+ */
+AudioNode.prototype.addEventListener = function(type, listener,
+    opt_useCapture) {};
+
+/**
+ * @override
+ */
+AudioNode.prototype.removeEventListener = function(type, listener,
+    opt_useCapture) {};
+
+/**
+ * @override
+ * @return {boolean}
+ */
+AudioNode.prototype.dispatchEvent = function(evt) {};
+
+/**
+ * @param {!AudioNode|!AudioParam} destination
+ * @param {number=} output
+ * @param {number=} input
+ * @return {AudioNode|void}
+ */
+AudioNode.prototype.connect = function(destination, output, input) {};
+
+/**
+ * @param {!AudioNode|!AudioParam|number=} destination
+ * @param {number=} output
+ * @param {number=} input
+ */
+AudioNode.prototype.disconnect = function(destination, output, input) {};
+
+/** @type {!AudioContext} */
+AudioNode.prototype.context;
+
+/** @type {number} */
+AudioNode.prototype.numberOfInputs;
+
+/** @type {number} */
+AudioNode.prototype.numberOfOutputs;
+
+/** @type {number} */
+AudioNode.prototype.channelCount;
+
+/**
+ * @type {string}
+ * See https://www.w3.org/TR/webaudio/#the-audionode-interface for valid values
+ */
+AudioNode.prototype.channelCountMode;
+
+/**
+ * @type {string}
+ * See https://www.w3.org/TR/webaudio/#the-audionode-interface for valid values
+ */
+AudioNode.prototype.channelInterpretation;
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function AudioSourceNode() {}
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function AudioDestinationNode() {}
+
+/**
+ * @deprecated Use AudioDestinationNode#maxChannelCount
+ * @type {number}
+ */
+AudioDestinationNode.prototype.numberOfChannels;
+
+/** @type {number} */
+AudioDestinationNode.prototype.maxChannelCount;
+
+/**
+ * @constructor
+ */
+function AudioParam() {}
+
+/** @type {number} */
+AudioParam.prototype.value;
+
+/**
+ * @type {string}
+ * See https://www.w3.org/TR/webaudio/#dom-audioparam-automationrate for valid
+ * values.
+ */
+AudioParam.prototype.automationRate;
+
+/**
+ * @deprecated
+ * @type {number}
+ */
+AudioParam.prototype.maxValue;
+
+/**
+ * @deprecated
+ * @type {number}
+ */
+AudioParam.prototype.minValue;
+
+/** @type {number} */
+AudioParam.prototype.defaultValue;
+
+/**
+ * @deprecated
+ * @type {number}
+ */
+AudioParam.prototype.units;
+
+/**
+ * @param {number} value
+ * @param {number} startTime
+ * @return {!AudioParam}
+ * @throws {!TypeError} if startTime is negative or not a finite number
+ */
+AudioParam.prototype.setValueAtTime = function(value, startTime) {};
+
+/**
+ * @param {number} value
+ * @param {number} endTime
+ * @return {!AudioParam}
+ * @throws {!TypeError} if endTime is negative or not a finite number
+ */
+AudioParam.prototype.linearRampToValueAtTime = function(value, endTime) {};
+
+/**
+ * @param {number} value
+ * @param {number} endTime
+ * @return {!AudioParam}
+ * @throws {!TypeError} if endTime is negative or not a finite number
+ */
+AudioParam.prototype.exponentialRampToValueAtTime = function(value, endTime) {};
+
+/**
+ * @param {number} target
+ * @param {number} startTime
+ * @param {number} timeConstant
+ * @return {!AudioParam}
+ * @throws {!TypeError} if startTime is negative or not a finite number, or
+ * timeConstant is not strictly positive
+ */
+AudioParam.prototype.setTargetAtTime = function(target, startTime,
+    timeConstant) {};
+
+/**
+ * @deprecated Use setTargetAtTime instead.
+ * @param {number} target
+ * @param {number} startTime
+ * @param {number} timeConstant
+ * @return {!AudioParam}
+ */
+AudioParam.prototype.setTargetValueAtTime = function(target, startTime,
+    timeConstant) {};
+
+/**
+ * @param {!Float32Array} values
+ * @param {number} startTime
+ * @param {number} duration
+ * @return {!AudioParam}
+ * @throws {!TypeError} if startTime is negative or not a finite number
+ */
+AudioParam.prototype.setValueCurveAtTime = function(values, startTime,
+    duration) {};
+
+/**
+ * @param {number} startTime
+ * @return {!AudioParam}
+ * @throws {!TypeError} if startTime is negative or not a finite number
+ */
+AudioParam.prototype.cancelScheduledValues = function(startTime) {};
+
+/**
+ * @constructor
+ * @extends {AudioParam}
+ */
+function AudioGain() {}
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function GainNode() {}
+
+/** @type {!AudioParam} */
+GainNode.prototype.gain;
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function DelayNode() {}
+
+/** @type {!AudioParam} */
+DelayNode.prototype.delayTime;
+
+/**
+ * @constructor
+ */
+function AudioBuffer() {}
+
+/**
+ * @deprecated
+ * @type {!AudioGain}
+ */
+AudioBuffer.prototype.gain;
+
+/** @type {number} */
+AudioBuffer.prototype.sampleRate;
+
+/** @type {number} */
+AudioBuffer.prototype.length;
+
+/** @type {number} */
+AudioBuffer.prototype.duration;
+
+/** @type {number} */
+AudioBuffer.prototype.numberOfChannels;
+
+/**
+ * @param {number} channel
+ * @return {!Float32Array}
+ */
+AudioBuffer.prototype.getChannelData = function(channel) {};
+
+/**
+ * @param  {!Float32Array} destination
+ * @param  {number} channelNumber
+ * @param  {number=} startInChannel
+ */
+AudioBuffer.prototype.copyFromChannel = function(destination,
+    channelNumber, startInChannel) {};
+
+/**
+ * @param  {!Float32Array} source
+ * @param  {number} channelNumber
+ * @param  {number=} startInChannel
+ */
+AudioBuffer.prototype.copyToChannel = function(source, channelNumber,
+    startInChannel) {};
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function AudioBufferSourceNode() {}
+
+/**
+ * @deprecated
+ * @const {number}
+ */
+AudioBufferSourceNode.prototype.UNSCHEDULED_STATE;
+
+/**
+ * @deprecated
+ * @const {number}
+ */
+AudioBufferSourceNode.prototype.SCHEDULED_STATE;
+
+/**
+ * @deprecated
+ * @const {number}
+ */
+AudioBufferSourceNode.prototype.PLAYING_STATE;
+
+/**
+ * @deprecated
+ * @const {number}
+ */
+AudioBufferSourceNode.prototype.FINISHED_STATE;
+
+/**
+ * @deprecated
+ * @type {number}
+ */
+AudioBufferSourceNode.prototype.playbackState;
+
+/** @type {AudioBuffer} */
+AudioBufferSourceNode.prototype.buffer;
+
+/**
+ * @deprecated
+ * @type {number}
+ */
+AudioBufferSourceNode.prototype.gain;
+
+/** @type {!AudioParam} */
+AudioBufferSourceNode.prototype.playbackRate;
+
+/** @type {boolean} */
+AudioBufferSourceNode.prototype.loop;
+
+/** @type {number} */
+AudioBufferSourceNode.prototype.loopStart;
+
+/** @type {number} */
+AudioBufferSourceNode.prototype.loopEnd;
+
+/** @type {?function(!Event): void} */
+AudioBufferSourceNode.prototype.onended;
+
+/** @type {!AudioParam} */
+AudioBufferSourceNode.prototype.detune;
+
+/**
+ * @param {number=} when
+ * @param {number=} opt_offset
+ * @param {number=} opt_duration
+ * @throws {!TypeError} if any parameter is negative
+ */
+AudioBufferSourceNode.prototype.start = function(when, opt_offset,
+    opt_duration) {};
+
+/**
+ * @param {number=} when
+ * @throws {!TypeError} if when is negative
+ */
+AudioBufferSourceNode.prototype.stop = function(when) {};
+
+/**
+ * @deprecated Use AudioBufferSourceNode#start
+ * @param {number} when
+ * @return {undefined}
+ */
+AudioBufferSourceNode.prototype.noteOn = function(when) {};
+
+/**
+ * @param {number=} when
+ * @param {number=} opt_offset
+ * @param {number=} opt_duration
+ * @deprecated Use AudioBufferSourceNode#start
+ */
+AudioBufferSourceNode.prototype.noteGrainOn = function(when, opt_offset,
+    opt_duration) {};
+
+/**
+ * @param {number} when
+ * @deprecated Use AudioBufferSourceNode#stop
+ */
+AudioBufferSourceNode.prototype.noteOff = function(when) {};
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function MediaElementAudioSourceNode() {}
+
+/**
+ * @constructor
+ */
+function AudioWorker() {}
+
+/** @type {?function(!Event)} */
+AudioWorker.prototype.onloaded;
+
+/** @type {?function(!Event)} */
+AudioWorker.prototype.onmessage;
+
+/** @type {!Array<!AudioWorkerParamDescriptor>} */
+AudioWorker.prototype.parameters;
+
+/**
+ * @param  {string} name
+ * @param  {number} defaultValue
+ * @return {!AudioParam}
+ */
+AudioWorker.prototype.addParameter = function(name, defaultValue) {};
+
+/**
+ * @param  {number} numberOfInputs
+ * @param  {number} numberOfOutputs
+ * @return {!AudioWorkerNode}
+ */
+AudioWorker.prototype.createNode = function(numberOfInputs, numberOfOutputs) {};
+
+/**
+ * @param  {*} message
+ * @param  {!Array<!Transferable>=} transfer
+ */
+AudioWorker.prototype.postMessage = function(message, transfer) {};
+
+/**
+ * @param  {string} name
+ */
+AudioWorker.prototype.removeParameter = function(name) {};
+
+/**
+ */
+AudioWorker.prototype.terminate = function() {};
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function AudioWorkerNode() {}
+
+/** @type {?function(!Event)} */
+AudioWorkerNode.prototype.onmessage;
+
+/**
+ * @param  {*} message
+ * @param  {!Array<!Transferable>=} transfer
+ */
+AudioWorkerNode.prototype.postMessage = function(message, transfer) {};
+
+/**
+ * @constructor
+ */
+function AudioWorkerParamDescriptor() {}
+
+/** @type {number} */
+AudioWorkerParamDescriptor.prototype.defaultValue;
+
+/** @type {string} */
+AudioWorkerParamDescriptor.prototype.name;
+
+/**
+ * @constructor
+ */
+function AudioWorkerGlobalScope() {}
+
+/** @type {?function(!Event)} */
+AudioWorkerGlobalScope.prototype.onaudioprocess;
+
+/** @type {?function(!Event)} */
+AudioWorkerGlobalScope.prototype.onnodecreate;
+
+/** @type {!Array<!AudioWorkerParamDescriptor>} */
+AudioWorkerGlobalScope.prototype.parameters;
+
+/** @type {number} */
+AudioWorkerGlobalScope.prototype.sampleRate;
+
+/**
+ * @param  {string} name
+ * @param  {number} defaultValue
+ * @return {!AudioParam}
+ */
+AudioWorkerGlobalScope.prototype.addParameter = function(name, defaultValue) {};
+
+/**
+ * @param  {string} name
+ */
+AudioWorkerGlobalScope.prototype.removeParameter = function(name) {};
+
+/**
+ * @constructor
+ */
+function AudioWorkerNodeProcessor() {}
+
+/** @type {?function(!Event)} */
+AudioWorkerNodeProcessor.prototype.onmessage;
+
+/**
+ * @param  {*} message
+ * @param  {!Array<!Transferable>=} transfer
+ */
+AudioWorkerNodeProcessor.prototype.postMessage = function(message, transfer) {};
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ * @deprecated Use AudioWorkerNode
+ */
+function JavaScriptAudioNode() {}
+
+/**
+ * @type {EventListener|(function(!AudioProcessingEvent):(boolean|undefined))}
+ * @deprecated Use AudioWorkerNode
+ */
+JavaScriptAudioNode.prototype.onaudioprocess;
+
+/**
+ * @type {number}
+ * @deprecated Use AudioWorkerNode
+ */
+JavaScriptAudioNode.prototype.bufferSize;
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ * @deprecated Use AudioWorkerNode
+ */
+function ScriptProcessorNode() {}
+
+/**
+ * @type {EventListener|(function(!AudioProcessingEvent):(boolean|undefined))}
+ * @deprecated Use AudioWorkerNode
+ */
+ScriptProcessorNode.prototype.onaudioprocess;
+
+/**
+ * @type {number}
+ * @deprecated Use AudioWorkerNode
+ */
+ScriptProcessorNode.prototype.bufferSize;
+
+/**
+ * @constructor
+ * @extends {Event}
+ */
+function AudioWorkerNodeCreationEvent() {}
+
+/** @type {!Array} */
+AudioWorkerNodeCreationEvent.prototype.inputs;
+
+/** @type {!AudioWorkerNodeProcessor} */
+AudioWorkerNodeCreationEvent.prototype.node;
+
+/** @type {!Array} */
+AudioWorkerNodeCreationEvent.prototype.outputs;
+
+/**
+ * @constructor
+ * @extends {Event}
+ */
+function AudioProcessEvent() {}
+
+/** @type {!Float32Array} */
+AudioProcessEvent.prototype.inputs;
+
+/** @type {!AudioWorkerNodeProcessor} */
+AudioProcessEvent.prototype.node;
+
+/** @type {!Float32Array} */
+AudioProcessEvent.prototype.outputs;
+
+/** @type {!Object} */
+AudioProcessEvent.prototype.parameters;
+
+/** @type {number} */
+AudioProcessEvent.prototype.playbackTime;
+
+/**
+ * @constructor
+ * @extends {Event}
+ * @deprecated Use AudioProcessEvent
+ */
+function AudioProcessingEvent() {}
+
+/**
+ * @type {!ScriptProcessorNode}
+ * @deprecated Use AudioProcessEvent
+ */
+AudioProcessingEvent.prototype.node;
+
+/**
+ * @type {number}
+ * @deprecated Use AudioProcessEvent
+ */
+AudioProcessingEvent.prototype.playbackTime;
+
+/**
+ * @type {!AudioBuffer}
+ * @deprecated Use AudioProcessEvent
+ */
+AudioProcessingEvent.prototype.inputBuffer;
+
+/**
+ * @type {!AudioBuffer}
+ * @deprecated Use AudioProcessEvent
+ */
+AudioProcessingEvent.prototype.outputBuffer;
+
+/**
+ * @deprecated
+ * @constructor
+ * @extends {AudioNode}
+ */
+function AudioPannerNode() {}
+
+/**
+ * @deprecated
+ * @const {number}
+ */
+AudioPannerNode.prototype.EQUALPOWER;
+
+/**
+ * @deprecated
+ * @const {number}
+ */
+AudioPannerNode.prototype.HRTF;
+
+/**
+ * @deprecated
+ * @const {number}
+ */
+AudioPannerNode.prototype.SOUNDFIELD;
+
+/**
+ * @deprecated
+ * @const {number}
+ */
+AudioPannerNode.prototype.LINEAR_DISTANCE;
+
+/**
+ * @deprecated
+ * @const {number}
+ */
+AudioPannerNode.prototype.INVERSE_DISTANCE;
+
+/**
+ * @deprecated
+ * @const {number}
+ */
+AudioPannerNode.prototype.EXPONENTIAL_DISTANCE;
+
+/**
+ * @deprecated
+ * @type {number|string}
+ */
+AudioPannerNode.prototype.panningModel;
+
+/**
+ * @deprecated
+ * @param {number} x
+ * @param {number} y
+ * @param {number} z
+ * @return {undefined}
+ */
+AudioPannerNode.prototype.setPosition = function(x, y, z) {};
+
+/**
+ * @deprecated
+ * @param {number} x
+ * @param {number} y
+ * @param {number} z
+ * @return {undefined}
+ */
+AudioPannerNode.prototype.setOrientation = function(x, y, z) {};
+
+/**
+ * @deprecated
+ * @param {number} x
+ * @param {number} y
+ * @param {number} z
+ * @return {undefined}
+ */
+AudioPannerNode.prototype.setVelocity = function(x, y, z) {};
+
+/**
+ * @deprecated
+ * @type {number|string}
+ */
+AudioPannerNode.prototype.distanceModel;
+
+/**
+ * @deprecated
+ * @type {number}
+ */
+AudioPannerNode.prototype.refDistance;
+
+/**
+ * @deprecated
+ * @type {number}
+ */
+AudioPannerNode.prototype.maxDistance;
+
+/**
+ * @deprecated
+ * @type {number}
+ */
+AudioPannerNode.prototype.rolloffFactor;
+
+/**
+ * @deprecated
+ * @type {number}
+ */
+AudioPannerNode.prototype.coneInnerAngle;
+
+/**
+ * @deprecated
+ * @type {number}
+ */
+AudioPannerNode.prototype.coneOuterAngle;
+
+/**
+ * @deprecated
+ * @type {number}
+ */
+AudioPannerNode.prototype.coneOuterGain;
+
+/**
+ * @deprecated
+ * @type {!AudioGain}
+ */
+AudioPannerNode.prototype.coneGain;
+
+/**
+ * @deprecated
+ * @type {!AudioGain}
+ */
+AudioPannerNode.prototype.distanceGain;
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function PannerNode() {}
+
+/** @type {number} */
+PannerNode.prototype.coneInnerAngle;
+
+/** @type {number} */
+PannerNode.prototype.coneOuterAngle;
+
+/** @type {number} */
+PannerNode.prototype.coneOuterGain;
+
+/**
+ * @type {string}
+ * See https://www.w3.org/TR/webaudio/#the-pannernode-interface for valid values
+ */
+PannerNode.prototype.distanceModel;
+
+/** @type {number} */
+PannerNode.prototype.maxDistance;
+
+/**
+ * @type {string}
+ * See https://www.w3.org/TR/webaudio/#the-pannernode-interface for valid values
+ */
+PannerNode.prototype.panningModel;
+
+/** @type {number} */
+PannerNode.prototype.refDistance;
+
+/** @type {number} */
+PannerNode.prototype.rolloffFactor;
+
+/**
+ * @param {number} x
+ * @param {number} y
+ * @param {number} z
+ */
+PannerNode.prototype.setOrientation = function(x, y, z) {};
+
+/**
+ * @param {number} x
+ * @param {number} y
+ * @param {number} z
+ */
+PannerNode.prototype.setPosition = function(x, y, z) {};
+
+/**
+ * @param {number} x
+ * @param {number} y
+ * @param {number} z
+ */
+PannerNode.prototype.setVelocity = function(x, y, z) {};
+
+/**
+ * @constructor
+ * @deprecated Use SpatialListener
+ */
+function AudioListener() {}
+
+/**
+ * @type {number}
+ * @deprecated Use SpatialListener
+ */
+AudioListener.prototype.gain;
+
+/**
+ * @type {number}
+ * @deprecated Use SpatialListener
+ */
+AudioListener.prototype.dopplerFactor;
+
+/**
+ * @type {number}
+ * @deprecated Use SpatialListener
+ */
+AudioListener.prototype.speedOfSound;
+
+/**
+ * @param {number} x
+ * @param {number} y
+ * @param {number} z
+ * @deprecated Use SpatialListener
+ */
+AudioListener.prototype.setPosition = function(x, y, z) {};
+
+/**
+ * @param {number} x
+ * @param {number} y
+ * @param {number} z
+ * @param {number} xUp
+ * @param {number} yUp
+ * @param {number} zUp
+ * @deprecated Use SpatialListener
+ */
+AudioListener.prototype.setOrientation = function(x, y, z, xUp, yUp, zUp) {};
+
+/**
+ * @param {number} x
+ * @param {number} y
+ * @param {number} z
+ * @deprecated Use SpatialListener
+ */
+AudioListener.prototype.setVelocity = function(x, y, z) {};
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function SpatialPannerNode() {}
+
+/** @type {number} */
+SpatialPannerNode.prototype.coneInnerAngle;
+
+/** @type {number} */
+SpatialPannerNode.prototype.coneOuterAngle;
+
+/** @type {number} */
+SpatialPannerNode.prototype.coneOuterGain;
+
+/**
+ * @type {string}
+ * See https://www.w3.org/TR/webaudio/#the-pannernode-interface for valid values
+ */
+SpatialPannerNode.prototype.distanceModel;
+
+/** @type {number} */
+SpatialPannerNode.prototype.maxDistance;
+
+/** @type {!AudioParam} */
+SpatialPannerNode.prototype.orientationX;
+
+/** @type {!AudioParam} */
+SpatialPannerNode.prototype.orientationY;
+
+/** @type {!AudioParam} */
+SpatialPannerNode.prototype.orientationZ;
+
+/**
+ * @type {string}
+ * See https://www.w3.org/TR/webaudio/#the-pannernode-interface for valid values
+ */
+SpatialPannerNode.prototype.panningModel;
+
+/** @type {!AudioParam} */
+SpatialPannerNode.prototype.positionX;
+
+/** @type {!AudioParam} */
+SpatialPannerNode.prototype.positionY;
+
+/** @type {!AudioParam} */
+SpatialPannerNode.prototype.positionZ;
+
+/** @type {number} */
+SpatialPannerNode.prototype.refDistance;
+
+/** @type {number} */
+SpatialPannerNode.prototype.rolloffFactor;
+
+/**
+ * @constructor
+ */
+function SpatialListener() {}
+
+/** @type {!AudioParam} */
+SpatialListener.prototype.forwardX;
+
+/** @type {!AudioParam} */
+SpatialListener.prototype.forwardY;
+
+/** @type {!AudioParam} */
+SpatialListener.prototype.forwardZ;
+
+/** @type {!AudioParam} */
+SpatialListener.prototype.positionX;
+
+/** @type {!AudioParam} */
+SpatialListener.prototype.positionY;
+
+/** @type {!AudioParam} */
+SpatialListener.prototype.positionZ;
+
+/** @type {!AudioParam} */
+SpatialListener.prototype.upX;
+
+/** @type {!AudioParam} */
+SpatialListener.prototype.upY;
+
+/** @type {!AudioParam} */
+SpatialListener.prototype.upZ;
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ * @see http://webaudio.github.io/web-audio-api/#the-stereopannernode-interface
+ */
+function StereoPannerNode() {}
+
+/** @type {!AudioParam} */
+StereoPannerNode.prototype.pan;
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function ConvolverNode() {}
+
+/** @type {?AudioBuffer} */
+ConvolverNode.prototype.buffer;
+
+/** @type {boolean} */
+ConvolverNode.prototype.normalize;
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+var AnalyserNode = function() {};
+
+/**
+ * @param {!Float32Array} array
+ */
+AnalyserNode.prototype.getFloatFrequencyData = function(array) {};
+
+/**
+ * @param {!Uint8Array} array
+ */
+AnalyserNode.prototype.getByteFrequencyData = function(array) {};
+
+/**
+ * @param {!Uint8Array} array
+ */
+AnalyserNode.prototype.getByteTimeDomainData = function(array) {};
+
+/**
+ * @param {!Float32Array} array
+ */
+AnalyserNode.prototype.getFloatTimeDomainData = function(array) {};
+
+/** @type {number} */
+AnalyserNode.prototype.fftSize;
+
+/** @type {number} */
+AnalyserNode.prototype.frequencyBinCount;
+
+/** @type {number} */
+AnalyserNode.prototype.minDecibels;
+
+/** @type {number} */
+AnalyserNode.prototype.maxDecibels;
+
+/** @type {number} */
+AnalyserNode.prototype.smoothingTimeConstant;
+
+/**
+ * @constructor
+ * @extends {AnalyserNode}
+ * @deprecated Use AnalyserNode
+ *
+ * This constructor has been added for backwards compatibility.
+ */
+var RealtimeAnalyserNode = function() {};
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function ChannelSplitterNode() {}
+
+/**
+ * @constructor
+ * @extends {ChannelSplitterNode}
+ * @deprecated Use ChannelSplitterNode
+ *
+ * This constructor has been added for backwards compatibility.
+ */
+function AudioChannelSplitter() {}
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function ChannelMergerNode() {}
+
+/**
+ * @constructor
+ * @extends {ChannelMergerNode}
+ * @deprecated Use ChannelMergerNode
+ *
+ * This constructor has been added for backwards compatibility.
+ */
+function AudioChannelMerger() {}
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function DynamicsCompressorNode() {}
+
+/** @type {!AudioParam} */
+DynamicsCompressorNode.prototype.threshold;
+
+/** @type {!AudioParam} */
+DynamicsCompressorNode.prototype.knee;
+
+/** @type {!AudioParam} */
+DynamicsCompressorNode.prototype.ratio;
+
+/** @type {number} */
+DynamicsCompressorNode.prototype.reduction;
+
+/** @type {!AudioParam} */
+DynamicsCompressorNode.prototype.attack;
+
+/** @type {!AudioParam} */
+DynamicsCompressorNode.prototype.release;
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function BiquadFilterNode() {}
+
+/**
+ * A read-able and write-able string that specifies the type of the filter.
+ * See http://webaudio.github.io/web-audio-api/#the-biquadfilternode-interface
+ * for valid values.
+ * @type {string}
+ */
+BiquadFilterNode.prototype.type;
+
+/** @type {!AudioParam} */
+BiquadFilterNode.prototype.frequency;
+
+/** @type {!AudioParam} */
+BiquadFilterNode.prototype.detune;
+
+/** @type {!AudioParam} */
+BiquadFilterNode.prototype.Q;
+
+/** @type {!AudioParam} */
+BiquadFilterNode.prototype.gain;
+/**
+ * @param {Float32Array} frequencyHz
+ * @param {Float32Array} magResponse
+ * @param {Float32Array} phaseResponse
+ * @return {undefined}
+ */
+BiquadFilterNode.prototype.getFrequencyResponse = function(
+    frequencyHz, magResponse, phaseResponse) {};
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function IIRFilterNode() {}
+
+/**
+ * @param {!Float32Array} frequencyHz
+ * @param {!Float32Array} magResponse
+ * @param {!Float32Array} phaseResponse
+ * @return {undefined}
+ */
+IIRFilterNode.prototype.getFrequencyResponse = function(
+    frequencyHz, magResponse, phaseResponse) {};
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function WaveShaperNode() {}
+
+/** @type {Float32Array} */
+WaveShaperNode.prototype.curve;
+
+/** @type {string} */
+WaveShaperNode.prototype.oversample;
+
+/**
+ * @deprecated
+ * @constructor
+ */
+function WaveTable() {}
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function OscillatorNode() {}
+
+/**
+ * @type {string}
+ * See https://www.w3.org/TR/webaudio/#the-oscillatornode-interface for valid values
+ */
+OscillatorNode.prototype.type;
+
+/**
+ * @deprecated
+ * @type {number}
+ */
+OscillatorNode.prototype.playbackState;
+
+/** @type {!AudioParam} */
+OscillatorNode.prototype.frequency;
+
+/** @type {!AudioParam} */
+OscillatorNode.prototype.detune;
+
+/**
+ * @param {number=} when
+ */
+OscillatorNode.prototype.start = function(when) {};
+
+/**
+ * @param {number=} when
+ */
+OscillatorNode.prototype.stop = function(when) {};
+
+/**
+ * @deprecated
+ * @param {!WaveTable} waveTable
+ */
+OscillatorNode.prototype.setWaveTable = function(waveTable) {};
+
+/**
+ * @param {!PeriodicWave} periodicWave
+ */
+OscillatorNode.prototype.setPeriodicWave = function(periodicWave) {};
+
+/** @type {?function(!Event)} */
+OscillatorNode.prototype.onended;
+
+/**
+ * @constructor
+ */
+function PeriodicWave() {}
+
+/**
+ * @record
+ * @see https://www.w3.org/TR/webaudio/#dictdef-constantsourceoptions
+ */
+function ConstantSourceOptions() {};
+
+/** @const {(number|undefined)} */
+ConstantSourceOptions.offset;
+
+/**
+ * @param {!BaseAudioContext} context
+ * @param {!ConstantSourceOptions=} options
+ * @constructor
+ * @extends {AudioNode}
+ * @see https://www.w3.org/TR/webaudio/#ConstantSourceNode
+ */
+function ConstantSourceNode(context, options) {}
+
+/**
+ * @param {number=} when
+ */
+ConstantSourceNode.prototype.start = function(when) {};
+
+/**
+ * @param {number=} when
+ */
+ConstantSourceNode.prototype.stop = function(when) {};
+
+/** @type {!AudioParam} */
+ConstantSourceNode.prototype.offset;
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function MediaStreamAudioSourceNode() {}
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ */
+function MediaStreamAudioDestinationNode() {}
+
+/** @type {!MediaStream} */
+MediaStreamAudioDestinationNode.prototype.stream;
+
+/**
+ * @constructor
+ * @see https://www.w3.org/TR/webaudio/#audioworklet
+ * @implements {Worklet}
+ */
+function AudioWorklet() {}
+
+/**
+ * @constructor
+ * @see https://www.w3.org/TR/webaudio/#audioworkletglobalscope
+ * @implements {WorkletGlobalScope}
+ */
+function AudioWorkletGlobalScope() {}
+
+/** @type {number} */
+AudioWorkletGlobalScope.prototype.currentFrame;
+
+/** @type {number} */
+AudioWorkletGlobalScope.prototype.currentTime;
+
+/** @type {number} */
+AudioWorkletGlobalScope.prototype.sampleRate;
+
+/**
+ * @param {!string} name
+ * @param {!function()} processorCtor
+ */
+AudioWorkletGlobalScope.prototype.registerProcessor = function(
+    name, processorCtor) {};
+
+/**
+ * @constructor
+ * @extends {AudioNode}
+ * @param {!BaseAudioContext} context
+ * @param {string} name
+ * @param {!AudioWorkletNodeOptions=} options
+ * @see https://www.w3.org/TR/webaudio/#audioworkletnode
+ */
+function AudioWorkletNode(context, name, options) {}
+
+/** @type {!EventListener|function()} */
+AudioWorkletNode.prototype.onprocesserror;
+
+/** @type {!Object<string, !AudioParam>} */
+AudioWorkletNode.prototype.parameters;
+
+/** @type {!MessagePort} */
+AudioWorkletNode.prototype.port;
+
+/**
+ * @record
+ * @see https://webaudio.github.io/web-audio-api/#dictdef-audioworkletnodeoptions
+ */
+function AudioWorkletNodeOptions() {};
+
+/** @type {number} */
+AudioWorkletNodeOptions.prototype.numberOfInputs;
+
+/** @type {number} */
+AudioWorkletNodeOptions.prototype.numberOfOutputs;
+
+/** @type {!Array<number>} */
+AudioWorkletNodeOptions.prototype.outputChannelCount;
+
+/** @type {!Object<string, number>} */
+AudioWorkletNodeOptions.prototype.parameterData;
+
+/** @type {?Object} */
+AudioWorkletNodeOptions.prototype.processorOptions;
+
+/**
+ * @constructor
+ * @param {!AudioWorkletNodeOptions=} options
+ * @see https://www.w3.org/TR/webaudio/#audioworkletprocessor
+ */
+function AudioWorkletProcessor(options) {}
+
+/** @type {!MessagePort} */
+AudioWorkletProcessor.prototype.port;
+
+/**
+ * @param {!Array<!Array<!Float32Array>>} inputs
+ * @param {!Array<!Array<!Float32Array>>} outputs
+ * @param {!Object<string, !Float32Array>} parameters
+ * @return {boolean}
+ */
+AudioWorkletProcessor.prototype.process = function(
+    inputs, outputs, parameters) {};
+
+/**
+ * @record
+ * @see https://www.w3.org/TR/webaudio/#dictdef-audioparamdescriptor
+ */
+function AudioParamDescriptor() {};
+
+/**
+ * @type {string}
+ * See https://www.w3.org/TR/webaudio/#dom-audioparam-automationrate for valid
+ * values.
+ */
+AudioParamDescriptor.prototype.automationRate;
+
+/** @type {number} */
+AudioParamDescriptor.prototype.defaultValue;
+
+/** @type {number} */
+AudioParamDescriptor.prototype.maxValue;
+
+/** @type {number} */
+AudioParamDescriptor.prototype.minValue;
+
+/** @type {string} */
+AudioParamDescriptor.prototype.name;
diff --git a/javascript/externs/web/w3c_clipboard.js b/javascript/externs/web/w3c_clipboard.js
new file mode 100644
index 000000000000..bf8b441b0db2
--- /dev/null
+++ b/javascript/externs/web/w3c_clipboard.js
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2018 The Closure Compiler Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Declaration of the asynchronous clipboard Web API.
+ * @externs
+ */
+
+/**
+ * @interface
+ * @see https://w3c.github.io/clipboard-apis/#async-clipboard-api
+ */
+function Clipboard() {}
+
+/**
+ * @return {!Promise<string>}
+ */
+Clipboard.prototype.readText = function() {};
+
+/**
+ * @param {string} text
+ * @return {!Promise<void>}
+ */
+Clipboard.prototype.writeText = function(text) {};
+
+/** @const {!Clipboard} */
+Navigator.prototype.clipboard;
diff --git a/javascript/externs/web/w3c_clipboardevent.js b/javascript/externs/web/w3c_clipboardevent.js
new file mode 100644
index 000000000000..16c6de5386cd
--- /dev/null
+++ b/javascript/externs/web/w3c_clipboardevent.js
@@ -0,0 +1,47 @@
+/*
+ * Copyright 2015 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for W3C's ClipboardEvent API.
+ * @see http://www.w3.org/TR/clipboard-apis/
+ *
+ * @externs
+ */
+
+
+
+/**
+ * @record
+ * @extends {EventInit}
+ * @see https://www.w3.org/TR/clipboard-apis/#dfn-eventinit
+ */
+function ClipboardEventInit() {}
+
+/** @type {?DataTransfer|undefined} */
+ClipboardEventInit.prototype.clipboardData;
+
+
+/**
+ * @constructor
+ * @extends {Event}
+ * @param {string} type
+ * @param {ClipboardEventInit=} opt_eventInitDict
+ */
+function ClipboardEvent(type, opt_eventInitDict) {}
+
+
+/** @const {?DataTransfer} */
+ClipboardEvent.prototype.clipboardData;
diff --git a/javascript/externs/web/w3c_composition_event.js b/javascript/externs/web/w3c_composition_event.js
new file mode 100644
index 000000000000..4aa48782eeb7
--- /dev/null
+++ b/javascript/externs/web/w3c_composition_event.js
@@ -0,0 +1,93 @@
+/*
+ * Copyright 2018 The Closure Compiler Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for W3C's Composition Events specification.
+ * @externs
+ */
+
+/**
+ * The `CompositionEvent` interface provides specific contextual information
+ * associated with Composition Events.
+ * @see https://www.w3.org/TR/uievents/#interface-compositionevent
+ * @record
+ * @extends {UIEventInit}
+ */
+function CompositionEventInit() {}
+
+/**
+ * `data` holds the value of the characters generated by an input method. This
+ * MAY be a single Unicode character or a non-empty sequence of Unicode
+ * characters. This attribute MAY be the empty string. The un-initialized value
+ * of this attribute MUST be "" (the empty string).
+ * @type {string}
+ */
+CompositionEventInit.prototype.data;
+
+/**
+ * Composition Events provide a means for inputing text in a supplementary or
+ * alternate manner than by Keyboard Events, in order to allow the use of
+ * characters that might not be commonly available on keyboard. For example,
+ * Composition Events might be used to add accents to characters despite their
+ * absence from standard US keyboards, to build up logograms of many Asian
+ * languages from their base components or categories, to select word choices
+ * from a combination of key presses on a mobile device keyboard, or to convert
+ * voice commands into text using a speech recognition processor.
+ *
+ * Conceptually, a composition session consists of one `compositionstart` event,
+ * one or more `compositionupdate` events, and one `compositionend` event, with
+ * the value of the data attribute persisting between each stage of this event
+ * chain during each session.
+ *
+ * Not all IME systems or devices expose the necessary data to the DOM, so the
+ * active composition string (the "Reading Window" or "candidate selection" menu
+ * option) might not be available through this interface, in which case the
+ * selection MAY be represented by the empty string.
+ *
+ * @see https://www.w3.org/TR/uievents/#events-compositionevents
+ * @param {string} type
+ * @param {!CompositionEventInit=} opt_eventInitDict
+ * @extends {UIEvent}
+ * @constructor
+ */
+function CompositionEvent(type, opt_eventInitDict) {}
+
+/**
+ * Initializes attributes of a `CompositionEvent` object. This method has the
+ * same behavior as `UIEvent.initUIEvent()`. The value of `detail` remains
+ * undefined.
+ *
+ * @see https://www.w3.org/TR/uievents/#idl-interface-CompositionEvent-initializers
+ * @param {string} typeArg
+ * @param {boolean} canBubbleArg
+ * @param {boolean} cancelableArg
+ * @param {?Window} viewArg
+ * @param {string} dataArg
+ * @param {string} localeArg
+ * @return {undefined}
+ */
+CompositionEvent.prototype.initCompositionEvent = function(
+    typeArg, canBubbleArg, cancelableArg, viewArg, dataArg, localeArg) {};
+
+/**
+ * @type {string}
+ */
+CompositionEvent.prototype.data;
+
+/**
+ * @type {string}
+ */
+CompositionEvent.prototype.locale;
diff --git a/javascript/externs/web/w3c_eventsource.js b/javascript/externs/web/w3c_eventsource.js
new file mode 100644
index 000000000000..d490f4646b1b
--- /dev/null
+++ b/javascript/externs/web/w3c_eventsource.js
@@ -0,0 +1,110 @@
+/*
+ * Copyright 2012 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for W3C's EventSource API.
+ * @see https://html.spec.whatwg.org/multipage/server-sent-events.html#server-sent-events
+ *
+ * @externs
+ */
+
+/** @record */
+function EventSourceInit() {};
+
+/** @type {(boolean|undefined)} */
+EventSourceInit.prototype.withCredentials;
+
+/**
+ * @constructor
+ * @implements {EventTarget}
+ * @param {string} url
+ * @param {EventSourceInit=} opt_eventSourceInitDict
+ */
+function EventSource(url, opt_eventSourceInitDict) {}
+
+/** @override */
+EventSource.prototype.addEventListener = function(type, listener, opt_options) {
+};
+
+/** @override */
+EventSource.prototype.removeEventListener = function(
+    type, listener, opt_options) {};
+
+/** @override */
+EventSource.prototype.dispatchEvent = function(evt) {};
+
+/**
+ * @const {string}
+ */
+EventSource.prototype.url;
+
+/** @const {boolean} */
+EventSource.prototype.withCredentials;
+
+/**
+ * @const {number}
+ */
+EventSource.prototype.CONNECTING;
+
+/**
+ * @const {number}
+ */
+EventSource.CONNECTING;
+
+/**
+ * @const {number}
+ */
+EventSource.prototype.OPEN;
+
+/**
+ * @const {number}
+ */
+EventSource.OPEN;
+
+/**
+ * @const {number}
+ */
+EventSource.prototype.CLOSED;
+
+/**
+ * @const {number}
+ */
+EventSource.CLOSED;
+
+/**
+ * @const {number}
+ */
+EventSource.prototype.readyState;
+
+/**
+ * @type {?function(!Event): void}
+ */
+EventSource.prototype.onopen = function(e) {};
+
+/**
+ * @type {?function(!MessageEvent<string>): void}
+ */
+EventSource.prototype.onmessage = function(e) {};
+
+/**
+ * @type {?function(!Event): void}
+ */
+EventSource.prototype.onerror = function(e) {};
+
+/**
+ * @return {undefined}
+ */
+EventSource.prototype.close = function() {};
diff --git a/javascript/externs/web/w3c_fileapi.js b/javascript/externs/web/w3c_fileapi.js
new file mode 100644
index 000000000000..353b58f6938c
--- /dev/null
+++ b/javascript/externs/web/w3c_fileapi.js
@@ -0,0 +1,295 @@
+/*
+ * Copyright 2010 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/**
+ * @fileoverview Definitions for objects in the File API, File Writer API, and
+ * File System API. Details of the API are at:
+ * http://www.w3.org/TR/FileAPI/
+ *
+ * @externs
+ */
+
+/** @record */
+function BlobPropertyBag() {};
+
+/** @type {(string|undefined)} */
+BlobPropertyBag.prototype.type;
+
+/**
+ * @see http://dev.w3.org/2006/webapi/FileAPI/#dfn-Blob
+ * @param {Array<ArrayBuffer|ArrayBufferView|Blob|string>=} opt_blobParts
+ * @param {BlobPropertyBag=} opt_options
+ * @constructor
+ * @nosideeffects
+ */
+function Blob(opt_blobParts, opt_options) {}
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-size
+ * @type {number}
+ */
+Blob.prototype.size;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-type
+ * @type {string}
+ */
+Blob.prototype.type;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-slice
+ * @param {number=} start
+ * @param {number=} length
+ * @param {string=} opt_contentType
+ * @return {!Blob}
+ * @nosideeffects
+ */
+Blob.prototype.slice = function(start, length, opt_contentType) {};
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#arraybuffer-method-algo
+ * @return {!Promise<!ArrayBuffer>}
+ * @nosideeffects
+ */
+Blob.prototype.arrayBuffer = function() {};
+
+/**
+ * @see https://www.w3.org/TR/FileAPI/#dom-blob-text
+ * @return {!Promise<string>}
+ * @nosideeffects
+ */
+Blob.prototype.text = function() {};
+
+
+/**
+ * @record
+ * @extends {BlobPropertyBag}
+ **/
+function FilePropertyBag() {};
+
+/** @type {(number|undefined)} */
+FilePropertyBag.prototype.lastModified;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-file
+ * @param {!Array<string|!Blob|!ArrayBuffer>=} contents
+ * @param {string=} name
+ * @param {FilePropertyBag=} properties
+ * @constructor
+ * @extends {Blob}
+ */
+function File(contents, name, properties) {}
+
+/**
+ * Chrome uses this instead of name.
+ * @deprecated Use name instead.
+ * @type {string}
+ */
+File.prototype.fileName;
+
+/**
+ * Chrome uses this instead of size.
+ * @deprecated Use size instead.
+ * @type {string}
+ */
+File.prototype.fileSize;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-name
+ * @type {string}
+ */
+File.prototype.name;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-lastModifiedDate
+ * @type {Date}
+ */
+File.prototype.lastModifiedDate;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-lastModified
+ * @type {number}
+ */
+File.prototype.lastModified;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-filereader
+ * @constructor
+ * @implements {EventTarget}
+ */
+function FileReader() {}
+
+/** @override */
+FileReader.prototype.addEventListener = function(type, listener, opt_options) {
+};
+
+/** @override */
+FileReader.prototype.removeEventListener = function(
+    type, listener, opt_options) {};
+
+/** @override */
+FileReader.prototype.dispatchEvent = function(evt) {};
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-readAsArrayBuffer
+ * @param {!Blob} blob
+ * @return {undefined}
+ */
+FileReader.prototype.readAsArrayBuffer = function(blob) {};
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-readAsBinaryStringAsync
+ * @param {!Blob} blob
+ * @return {undefined}
+ */
+FileReader.prototype.readAsBinaryString = function(blob) {};
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-readAsText
+ * @param {!Blob} blob
+ * @param {string=} encoding
+ * @return {undefined}
+ */
+FileReader.prototype.readAsText = function(blob, encoding) {};
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-readAsDataURL
+ * @param {!Blob} blob
+ * @return {undefined}
+ */
+FileReader.prototype.readAsDataURL = function(blob) {};
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-abort
+ * @return {undefined}
+ */
+FileReader.prototype.abort = function() {};
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-empty
+ * @const {number}
+ */
+FileReader.prototype.EMPTY;
+
+/** @const {number} */
+FileReader.EMPTY;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-loading
+ * @const {number}
+ */
+FileReader.prototype.LOADING;
+
+/** @const {number} */
+FileReader.LOADING;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-done
+ * @const {number}
+ */
+FileReader.prototype.DONE;
+
+/** @const {number} */
+FileReader.DONE;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-readystate
+ * @type {number}
+ */
+FileReader.prototype.readyState;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-result
+ * @type {string|Blob|ArrayBuffer}
+ */
+FileReader.prototype.result;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-error
+ * @type {DOMError}
+ */
+FileReader.prototype.error;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-onloadstart
+ * @type {?function(!ProgressEvent<!FileReader>)}
+ */
+FileReader.prototype.onloadstart;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-onprogress
+ * @type {?function(!ProgressEvent<!FileReader>)}
+ */
+FileReader.prototype.onprogress;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-onload
+ * @type {?function(!ProgressEvent<!FileReader>)}
+ */
+FileReader.prototype.onload;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-onabort
+ * @type {?function(!ProgressEvent<!FileReader>)}
+ */
+FileReader.prototype.onabort;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-onerror
+ * @type {?function(!ProgressEvent<!FileReader>)}
+ */
+FileReader.prototype.onerror;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-onloadend
+ * @type {?function(!ProgressEvent<!FileReader>)}
+ */
+FileReader.prototype.onloadend;
+
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#FileReaderSyncSync
+ * @constructor
+ */
+function FileReaderSync() {}
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-readAsArrayBufferSync
+ * @param {!Blob} blob
+ * @return {!ArrayBuffer}
+ */
+FileReaderSync.prototype.readAsArrayBuffer = function(blob) {};
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-readAsBinaryStringSync
+ * @param {!Blob} blob
+ * @return {string}
+ */
+FileReaderSync.prototype.readAsBinaryString = function(blob) {};
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-readAsTextSync
+ * @param {!Blob} blob
+ * @param {string=} encoding
+ * @return {string}
+ */
+FileReaderSync.prototype.readAsText = function(blob, encoding) {};
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-readAsDataURLSync
+ * @param {!Blob} blob
+ * @return {string}
+ */
+FileReaderSync.prototype.readAsDataURL = function(blob) {};
diff --git a/javascript/externs/web/w3c_geometry1.js b/javascript/externs/web/w3c_geometry1.js
new file mode 100644
index 000000000000..7a40715ad0dd
--- /dev/null
+++ b/javascript/externs/web/w3c_geometry1.js
@@ -0,0 +1,899 @@
+/*
+ * Copyright 2018 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for W3C's Geometry Interfaces Module Level 1 spec.
+ *  The whole file has been fully type annotated. Created from
+ *  https://www.w3.org/TR/geometry-1/
+ *
+ * @externs
+ */
+
+/**
+ * @deprecated ClientRect has been replaced by DOMRect in the latest spec.
+ * @constructor
+ * @see https://www.w3.org/TR/cssom-view/#changes-from-2011-08-04
+ */
+function ClientRect() {}
+
+/**
+ * @type {number}
+ * @see http://www.w3.org/TR/cssom-view/#dom-clientrect-top
+ */
+ClientRect.prototype.top;
+
+/**
+ * @type {number}
+ * @see http://www.w3.org/TR/cssom-view/#dom-clientrect-right
+ */
+ClientRect.prototype.right;
+
+/**
+ * @type {number}
+ * @see http://www.w3.org/TR/cssom-view/#dom-clientrect-bottom
+ */
+ClientRect.prototype.bottom;
+
+/**
+ * @type {number}
+ * @see http://www.w3.org/TR/cssom-view/#dom-clientrect-left
+ */
+ClientRect.prototype.left;
+
+/**
+ * @type {number}
+ * @see http://www.w3.org/TR/cssom-view/#dom-clientrect-width
+ */
+ClientRect.prototype.width;
+
+/**
+ * @type {number}
+ * @see http://www.w3.org/TR/cssom-view/#dom-clientrect-height
+ */
+ClientRect.prototype.height;
+
+/**
+ * @constructor
+ * @extends {ClientRect} for backwards compatibility
+ * @param {number=} x
+ * @param {number=} y
+ * @param {number=} width
+ * @param {number=} height
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrectreadonly-domrectreadonly
+ */
+function DOMRectReadOnly(x, y, width, height) {}
+
+/**
+ * @param {!DOMRectInit} other
+ * @return {!DOMRectReadOnly}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrectreadonly-fromrect
+ */
+DOMRectReadOnly.prototype.fromRect = function(other) {};
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrectreadonly-x
+ */
+DOMRectReadOnly.prototype.x;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrectreadonly-y
+ */
+DOMRectReadOnly.prototype.y;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrectreadonly-width
+ */
+DOMRectReadOnly.prototype.width;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrectreadonly-height
+ */
+DOMRectReadOnly.prototype.height;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrectreadonly-top
+ */
+DOMRectReadOnly.prototype.top;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrectreadonly-right
+ */
+DOMRectReadOnly.prototype.right;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrectreadonly-bottom
+ */
+DOMRectReadOnly.prototype.bottom;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrectreadonly-left
+ */
+DOMRectReadOnly.prototype.left;
+
+/**
+ * @constructor
+ * @extends {DOMRectReadOnly}
+ * @param {number=} x
+ * @param {number=} y
+ * @param {number=} width
+ * @param {number=} height
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrect-domrect
+ */
+function DOMRect(x, y, width, height) {}
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrect-x
+ */
+DOMRect.prototype.x;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrect-y
+ */
+DOMRect.prototype.y;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrect-width
+ */
+DOMRect.prototype.width;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrect-height
+ */
+DOMRect.prototype.height;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrectreadonly-top
+ */
+DOMRect.prototype.top;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrectreadonly-right
+ */
+DOMRect.prototype.right;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrectreadonly-bottom
+ */
+DOMRect.prototype.bottom;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrectreadonly-left
+ */
+DOMRect.prototype.left;
+
+/**
+ * @constructor
+ * @see https://www.w3.org/TR/geometry-1/#dictdef-domrectinit
+ */
+function DOMRectInit() {}
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrectinit-x
+ */
+DOMRectInit.prototype.x;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrectinit-y
+ */
+DOMRectInit.prototype.y;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrectinit-width
+ */
+DOMRectInit.prototype.width;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-domrectinit-height
+ */
+DOMRectInit.prototype.height;
+
+/**
+ * @constructor
+ * @param {number=} x
+ * @param {number=} y
+ * @param {number=} z
+ * @param {number=} w
+ * @see https://www.w3.org/TR/geometry-1/#dom-dompointreadonly-dompointreadonly
+ */
+function DOMPointReadOnly(x, y, z, w) {}
+
+/**
+ * @param {!DOMPointInit} other
+ * @return {!DOMPointReadOnly}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dompointreadonly-frompoint
+ */
+DOMPointReadOnly.prototype.fromPoint = function(other) {};
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dompointreadonly-x
+ */
+DOMPointReadOnly.prototype.x;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dompointreadonly-y
+ */
+DOMPointReadOnly.prototype.y;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dompointreadonly-z
+ */
+DOMPointReadOnly.prototype.z;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dompointreadonly-w
+ */
+DOMPointReadOnly.prototype.w;
+
+/**
+ * @constructor
+ * @extends {DOMPointReadOnly}
+ * @param {number=} x
+ * @param {number=} y
+ * @param {number=} z
+ * @param {number=} w
+ * @see https://www.w3.org/TR/geometry-1/#dom-dompoint-dompoint
+ */
+function DOMPoint(x, y, z, w) {}
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dompoint-x
+ */
+DOMPoint.prototype.x;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dompoint-y
+ */
+DOMPoint.prototype.y;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dompoint-z
+ */
+DOMPoint.prototype.z;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dompoint-w
+ */
+DOMPoint.prototype.w;
+
+/**
+ * @record
+ * @see https://www.w3.org/TR/geometry-1/#dictdef-dompointinit
+ */
+function DOMPointInit() {}
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dompointinit-x
+ */
+DOMPointInit.prototype.x;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dompointinit-y
+ */
+DOMPointInit.prototype.y;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dompointinit-z
+ */
+DOMPointInit.prototype.z;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dompointinit-w
+ */
+DOMPointInit.prototype.w;
+
+/**
+ * @constructor
+ * @implements {DOMMatrixInit}
+ * @param {string|Array<number>} init
+ * @see https://www.w3.org/TR/geometry-1/#dommatrixreadonly
+ */
+function DOMMatrixReadOnly(init) {}
+
+/**
+ * @param {!DOMMatrixInit} other
+ * @return {!DOMMatrixReadOnly}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-frommatrix
+ */
+DOMMatrixReadOnly.fromMatrix = function(other) {};
+
+/**
+ * @param {!Float32Array} array32
+ * @return {!DOMMatrixReadOnly}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-fromfloat32array
+ */
+DOMMatrixReadOnly.fromFloat32Array = function(array32) {};
+
+/**
+ * @param {!Float64Array} array64
+ * @return {!DOMMatrixReadOnly}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-fromfloat64array
+ */
+DOMMatrixReadOnly.fromFloat64Array = function(array64) {};
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-a
+ */
+DOMMatrixReadOnly.prototype.a;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-b
+ */
+DOMMatrixReadOnly.prototype.b;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-c
+ */
+DOMMatrixReadOnly.prototype.c;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-d
+ */
+DOMMatrixReadOnly.prototype.d;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-e
+ */
+DOMMatrixReadOnly.prototype.e;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-f
+ */
+DOMMatrixReadOnly.prototype.f;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-m11
+ */
+DOMMatrixReadOnly.prototype.m11;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-m12
+ */
+DOMMatrixReadOnly.prototype.m12;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-m13
+ */
+DOMMatrixReadOnly.prototype.m13;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-m14
+ */
+DOMMatrixReadOnly.prototype.m14;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-m21
+ */
+DOMMatrixReadOnly.prototype.m21;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-m22
+ */
+DOMMatrixReadOnly.prototype.m22;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-m23
+ */
+DOMMatrixReadOnly.prototype.m23;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-m24
+ */
+DOMMatrixReadOnly.prototype.m24;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-m31
+ */
+DOMMatrixReadOnly.prototype.m31;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-m32
+ */
+DOMMatrixReadOnly.prototype.m32;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-m33
+ */
+DOMMatrixReadOnly.prototype.m33;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-m34
+ */
+DOMMatrixReadOnly.prototype.m34;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-m41
+ */
+DOMMatrixReadOnly.prototype.m41;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-m42
+ */
+DOMMatrixReadOnly.prototype.m42;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-m43
+ */
+DOMMatrixReadOnly.prototype.m43;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-m44
+ */
+DOMMatrixReadOnly.prototype.m44;
+
+/**
+ * @type {boolean}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-is2d
+ */
+DOMMatrixReadOnly.prototype.is2D;
+
+/**
+ * @type {boolean}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-isidentity
+ */
+DOMMatrixReadOnly.prototype.isIdentity;
+
+/**
+ * @param {number=} tx
+ * @param {number=} ty
+ * @param {number=} tz
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-translate
+ */
+DOMMatrixReadOnly.prototype.translate = function(tx, ty, tz) {};
+
+/**
+ * @param {number=} scaleX
+ * @param {number=} scaleY
+ * @param {number=} scaleZ
+ * @param {number=} originX
+ * @param {number=} originY
+ * @param {number=} originZ
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-scale
+ */
+DOMMatrixReadOnly.prototype.scale = function(
+    scaleX, scaleY, scaleZ, originX, originY, originZ) {};
+
+/**
+ * @param {number=} scaleX
+ * @param {number=} scaleY
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-scalenonuniform
+ */
+DOMMatrixReadOnly.prototype.scaleNonUniform = function(scaleX, scaleY) {};
+
+/**
+ * @param {number=} scale
+ * @param {number=} originX
+ * @param {number=} originY
+ * @param {number=} originZ
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-scale3d
+ */
+DOMMatrixReadOnly.prototype.scale3d = function(
+    scale, originX, originY, originZ) {};
+
+/**
+ * @param {number=} rotX
+ * @param {number=} rotY
+ * @param {number=} rotZ
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-rotate
+ */
+DOMMatrixReadOnly.prototype.rotate = function(rotX, rotY, rotZ) {};
+
+/**
+ * @param {number=} x
+ * @param {number=} y
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-rotatefromvector
+ */
+DOMMatrixReadOnly.prototype.rotateFromVector = function(x, y) {};
+
+/**
+ * @param {number=} x
+ * @param {number=} y
+ * @param {number=} z
+ * @param {number=} angle
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-rotateaxisangle
+ */
+DOMMatrixReadOnly.prototype.rotateAxisAngle = function(x, y, z, angle) {};
+
+/**
+ * @param {number=} sx
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-skewx
+ */
+DOMMatrixReadOnly.prototype.skewX = function(sx) {};
+
+/**
+ * @param {number=} sy
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-skewy
+ */
+DOMMatrixReadOnly.prototype.skewY = function(sy) {};
+
+/**
+ * @param {!DOMMatrixInit} other
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-multiply
+ */
+DOMMatrixReadOnly.prototype.multiply = function(other) {};
+
+/**
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-flipx
+ */
+DOMMatrixReadOnly.prototype.flipX = function() {};
+
+/**
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-flipy
+ */
+DOMMatrixReadOnly.prototype.flipY = function() {};
+
+/**
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-inverse
+ */
+DOMMatrixReadOnly.prototype.inverse = function() {};
+
+/**
+ * @param {!DOMPointInit} point
+ * @return {!DOMPoint}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-transformpoint
+ */
+DOMMatrixReadOnly.prototype.transformPoint = function(point) {};
+
+/**
+ * @return {!Float32Array}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-tofloat32array
+ */
+DOMMatrixReadOnly.prototype.toFloat32Array = function() {};
+
+/**
+ * @return {!Float64Array}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixreadonly-tofloat64array
+ */
+DOMMatrixReadOnly.prototype.toFloat64Array = function() {};
+
+/**
+ * @constructor
+ * @extends {DOMMatrixReadOnly}
+ * @param {string|Array<number>} init
+ * @see https://www.w3.org/TR/geometry-1/#dommatrix
+ */
+function DOMMatrix(init) {}
+
+/**
+ * @param {!DOMMatrixInit} other
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix-frommatrix
+ */
+DOMMatrix.fromMatrix = function(other) {};
+
+/**
+ * @param {!Float32Array} array32
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix-fromfloat32array
+ */
+DOMMatrix.fromFloat32Array = function(array32) {};
+
+/**
+ * @param {!Float64Array} array64
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix-fromfloat64array
+ */
+DOMMatrix.fromFloat64Array = function(array64) {};
+
+/**
+ * @param {!DOMMatrixInit} other
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix-multiply
+ */
+DOMMatrix.prototype.multiplySelf = function(other) {};
+
+/**
+ * @param {!DOMMatrixInit} other
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix-premultiply
+ */
+DOMMatrix.prototype.preMultiplySelf = function(other) {};
+
+/**
+ * @param {number=} tx
+ * @param {number=} ty
+ * @param {number=} tz
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix-translate
+ */
+DOMMatrix.prototype.translateSelf = function(tx, ty, tz) {};
+
+/**
+ * @param {number=} scaleX
+ * @param {number=} scaleY
+ * @param {number=} scaleZ
+ * @param {number=} originX
+ * @param {number=} originY
+ * @param {number=} originZ
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix-scale
+ */
+DOMMatrix.prototype.scaleSelf = function(
+    scaleX, scaleY, scaleZ, originX, originY, originZ) {};
+
+/**
+ * @param {number=} scale
+ * @param {number=} originX
+ * @param {number=} originY
+ * @param {number=} originZ
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix-scale3d
+ */
+DOMMatrix.prototype.scale3dSelf = function(scale, originX, originY, originZ) {};
+
+/**
+ * @param {number=} rotX
+ * @param {number=} rotY
+ * @param {number=} rotZ
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix-rotate
+ */
+DOMMatrix.prototype.rotateSelf = function(rotX, rotY, rotZ) {};
+
+/**
+ * @param {number=} x
+ * @param {number=} y
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix-rotatefromvector
+ */
+DOMMatrix.prototype.rotateFromVectorSelf = function(x, y) {};
+
+/**
+ * @param {number=} x
+ * @param {number=} y
+ * @param {number=} z
+ * @param {number=} angle
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix-rotateaxisangle
+ */
+DOMMatrix.prototype.rotateAxisAngleSelf = function(x, y, z, angle) {};
+
+/**
+ * @param {number=} sx
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix-skewx
+ */
+DOMMatrix.prototype.skewXSelf = function(sx) {};
+
+/**
+ * @param {number=} sy
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix-skewy
+ */
+DOMMatrix.prototype.skewYSelf = function(sy) {};
+
+/**
+ * @return {!DOMMatrix}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix-inverse
+ */
+DOMMatrix.prototype.inverseSelf = function() {};
+
+/**
+ * @record
+ * @see https://www.w3.org/TR/geometry-1/#dictdef-dommatrix2dinit
+ */
+function DOMMatrix2DInit() {}
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix2dinit-a
+ */
+DOMMatrix2DInit.prototype.a;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix2dinit-b
+ */
+DOMMatrix2DInit.prototype.b;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix2dinit-c
+ */
+DOMMatrix2DInit.prototype.c;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix2dinit-d
+ */
+DOMMatrix2DInit.prototype.d;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix2dinit-e
+ */
+DOMMatrix2DInit.prototype.e;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix2dinit-f
+ */
+DOMMatrix2DInit.prototype.f;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix2dinit-m11
+ */
+DOMMatrix2DInit.prototype.m11;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix2dinit-m12
+ */
+DOMMatrix2DInit.prototype.m12;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix2dinit-m21
+ */
+DOMMatrix2DInit.prototype.m21;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix2dinit-m22
+ */
+DOMMatrix2DInit.prototype.m22;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix2dinit-m41
+ */
+DOMMatrix2DInit.prototype.m41;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrix2dinit-m42
+ */
+DOMMatrix2DInit.prototype.m42;
+
+/**
+ * @record
+ * @extends {DOMMatrix2DInit}
+ * @see https://www.w3.org/TR/geometry-1/#dictdef-dommatrix
+ */
+function DOMMatrixInit() {}
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixinit-m13
+ */
+DOMMatrixInit.prototype.m13;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixinit-m14
+ */
+DOMMatrixInit.prototype.m14;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixinit-m23
+ */
+DOMMatrixInit.prototype.m23;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixinit-m24
+ */
+DOMMatrixInit.prototype.m24;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixinit-m31
+ */
+DOMMatrixInit.prototype.m31;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixinit-m32
+ */
+DOMMatrixInit.prototype.m32;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixinit-m33
+ */
+DOMMatrixInit.prototype.m33;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixinit-m34
+ */
+DOMMatrixInit.prototype.m34;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixinit-m43
+ */
+DOMMatrixInit.prototype.m43;
+
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixinit-m44
+ */
+DOMMatrixInit.prototype.m44;
+
+/**
+ * @type {boolean}
+ * @see https://www.w3.org/TR/geometry-1/#dom-dommatrixinit-is2d
+ */
+DOMMatrixInit.prototype.is2D;
diff --git a/javascript/externs/web/w3c_keyboardlock.js b/javascript/externs/web/w3c_keyboardlock.js
new file mode 100644
index 000000000000..b532b32ae420
--- /dev/null
+++ b/javascript/externs/web/w3c_keyboardlock.js
@@ -0,0 +1,47 @@
+/*
+ * Copyright 2020 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for the W3C Keyboard Lock API.
+ * @see https://wicg.github.io/keyboard-lock/
+ * @externs
+ */
+
+/**
+ * Keyboard API object.
+ * @constructor
+ * @see https://w3c.github.io/keyboard-lock/#keyboard-interface
+ */
+function Keyboard() {}
+
+/**
+ * Lock the specified keys for this page, or all keys if keyCodes is omitted.
+ * @param {?Array<string>=} keyCodes
+ * @return {!Promise<undefined>}
+ */
+Keyboard.prototype.lock = function(keyCodes) {};
+
+/**
+ * Unlock any locked keys.
+ */
+Keyboard.prototype.unlock = function() {};
+
+
+/**
+ * @type {!Keyboard}
+ * @see https://w3c.github.io/keyboard-lock/#API
+ */
+Navigator.prototype.keyboard;
diff --git a/javascript/externs/web/w3c_mediacapabilities.js b/javascript/externs/web/w3c_mediacapabilities.js
new file mode 100644
index 000000000000..85b9691e6de5
--- /dev/null
+++ b/javascript/externs/web/w3c_mediacapabilities.js
@@ -0,0 +1,206 @@
+/*
+ * Copyright 2019 The Closure Compiler Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/**
+ * @fileoverview MediaCapabilities externs.
+ * Based on {@link https://w3c.github.io/media-capabilities/ MC draft 6 November
+ * 2019}.
+ * @externs
+ */
+
+/**
+ * @typedef {string}
+ * @see https://w3c.github.io/media-capabilities/#enumdef-hdrmetadatatype
+ */
+var HdrMetadataType;
+
+/**
+ * @typedef {string}
+ * @see https://w3c.github.io/media-capabilities/#enumdef-colorgamut
+ */
+var ColorGamut;
+
+/**
+ * @typedef {string}
+ * @see https://w3c.github.io/media-capabilities/#enumdef-transferfunction
+ */
+var TransferFunction;
+
+/**
+ * @typedef {string}
+ * @see https://w3c.github.io/media-capabilities/#enumdef-mediadecodingtype
+ */
+var MediaDecodingType;
+
+/**
+ * @typedef {string}
+ * @see https://w3c.github.io/media-capabilities/#enumdef-mediaencodingtype
+ */
+var MediaEncodingType;
+
+/**
+ * @typedef {{
+ *   contentType: string,
+ *   width: number,
+ *   height: number,
+ *   bitrate: number,
+ *   framerate: number,
+ *   hasAlphaChannel: (boolean|undefined),
+ *   hdrMetadataType: (!HdrMetadataType|undefined),
+ *   colorGamut: (!ColorGamut|undefined),
+ *   transferFunction: (!TransferFunction|undefined)
+ * }}
+ * @see https://w3c.github.io/media-capabilities/#dictdef-videoconfiguration
+ */
+var VideoConfiguration;
+
+// NOTE: channels definition below is not yet stable in the spec as of Dec 2019.
+// "The channels needs to be defined as a double (2.1, 4.1, 5.1, ...), an
+// unsigned short (number of channels) or as an enum value. The current
+// definition is a placeholder."
+/**
+ * @typedef {{
+ *   contentType: string,
+ *   channels: (*|undefined),
+ *   bitrate: (number|undefined),
+ *   samplerate: (number|undefined),
+ *   spatialRendering: (boolean|undefined)
+ * }}
+ * @see https://w3c.github.io/media-capabilities/#dictdef-audioconfiguration
+ */
+var AudioConfiguration;
+
+// NOTE: encryptionScheme is not yet in the MC spec as of Dec 2019, but has
+// already landed in EME and should be in MC soon.
+// https://github.com/w3c/media-capabilities/issues/100
+/**
+ * @typedef {{
+ *   robustness: (string|undefined),
+ *   encryptionScheme: (string|undefined)
+ * }}
+ * @see https://w3c.github.io/media-capabilities/#dictdef-keysystemtrackconfiguration
+ */
+var KeySystemTrackConfiguration;
+
+/**
+ * @typedef {{
+ *   keySystem: string,
+ *   initDataType: (string|undefined),
+ *   distinctiveIdentifier: (string|undefined),
+ *   persistentState: (string|undefined),
+ *   sessionTypes: (!Array<string>|undefined),
+ *   audio: (!KeySystemTrackConfiguration|undefined),
+ *   video: (!KeySystemTrackConfiguration|undefined)
+ * }}
+ * @see https://w3c.github.io/media-capabilities/#dictdef-mediacapabilitieskeysystemconfiguration
+ */
+var MediaCapabilitiesKeySystemConfiguration;
+
+/**
+ * @record
+ * @see https://w3c.github.io/media-capabilities/#dictdef-mediaconfiguration
+ */
+function MediaConfiguration() {}
+
+/** @type {!VideoConfiguration|undefined} */
+MediaConfiguration.prototype.video;
+
+/** @type {!AudioConfiguration|undefined} */
+MediaConfiguration.prototype.audio;
+
+/**
+ * @record
+ * @extends {MediaConfiguration}
+ * @see https://w3c.github.io/media-capabilities/#dictdef-mediadecodingconfiguration
+ */
+function MediaDecodingConfiguration() {}
+
+/** @type {!MediaDecodingType} */
+MediaDecodingConfiguration.prototype.type;
+
+/** @type {!MediaCapabilitiesKeySystemConfiguration|undefined} */
+MediaDecodingConfiguration.prototype.keySystemConfiguration;
+
+/**
+ * @record
+ * @extends {MediaConfiguration}
+ * @see https://w3c.github.io/media-capabilities/#dictdef-mediaencodingconfiguration
+ */
+function MediaEncodingConfiguration() {}
+
+/** @type {!MediaEncodingType} */
+MediaEncodingConfiguration.prototype.type;
+
+/**
+ * @record
+ * @see https://w3c.github.io/media-capabilities/#dictdef-mediacapabilitiesinfo
+ */
+function MediaCapabilitiesInfo() {}
+
+/** @type {boolean} */
+MediaCapabilitiesInfo.prototype.supported;
+
+/** @type {boolean} */
+MediaCapabilitiesInfo.prototype.smooth;
+
+/** @type {boolean} */
+MediaCapabilitiesInfo.prototype.powerEfficient;
+
+/**
+ * @record
+ * @extends {MediaCapabilitiesInfo}
+ * @see https://w3c.github.io/media-capabilities/#dictdef-mediacapabilitiesdecodinginfo
+ */
+function MediaCapabilitiesDecodingInfo() {}
+
+/** @type {?MediaKeySystemAccess} */
+MediaCapabilitiesDecodingInfo.prototype.keySystemAccess;
+
+/** @type {!MediaDecodingConfiguration} */
+MediaCapabilitiesDecodingInfo.prototype.configuration;
+
+/**
+ * @record
+ * @extends {MediaCapabilitiesInfo}
+ * @see https://w3c.github.io/media-capabilities/#dictdef-mediacapabilitiesencodinginfo
+ */
+function MediaCapabilitiesEncodingInfo() {}
+
+/** @type {!MediaEncodingConfiguration} */
+MediaCapabilitiesEncodingInfo.prototype.configuration;
+
+/**
+ * @interface
+ * @see https://w3c.github.io/media-capabilities/#mediacapabilities
+ */
+function MediaCapabilities() {}
+
+/**
+ * @param {!MediaDecodingConfiguration} configuration
+ * @return {!Promise<!MediaCapabilitiesDecodingInfo>}
+ */
+MediaCapabilities.prototype.decodingInfo = function(configuration) {};
+
+/**
+ * @param {!MediaEncodingConfiguration} configuration
+ * @return {!Promise<!MediaCapabilitiesEncodingInfo>}
+ */
+MediaCapabilities.prototype.encodingInfo = function(configuration) {};
+
+/** @const {?MediaCapabilities} */
+Navigator.prototype.mediaCapabilities;
+
+/** @const {?MediaCapabilities} */
+WorkerNavigator.prototype.mediaCapabilities;
diff --git a/javascript/externs/web/w3c_netinfo.js b/javascript/externs/web/w3c_netinfo.js
new file mode 100644
index 000000000000..8c3e6548cf0e
--- /dev/null
+++ b/javascript/externs/web/w3c_netinfo.js
@@ -0,0 +1,85 @@
+/*
+ * Copyright 2017 The Closure Compiler Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Externs for the Network Information API.
+ * @externs
+ */
+
+/**
+ * @see http://wicg.github.io/netinfo/#-dfn-networkinformation-dfn-interface
+ * @constructor
+ */
+function NetworkInformation() {}
+
+/** @type {ConnectionType} */
+NetworkInformation.prototype.type;
+
+/** @type {EffectiveConnectionType} */
+NetworkInformation.prototype.effectiveType;
+
+/** @type {Megabit} */
+NetworkInformation.prototype.downlinkMax;
+
+/** @type {Megabit} */
+NetworkInformation.prototype.downlink;
+
+/** @type {Millisecond} */
+NetworkInformation.prototype.rtt;
+
+/** @type {?function(Event)} */
+NetworkInformation.prototype.onchange;
+
+/** @type {boolean} */
+NetworkInformation.prototype.saveData;
+
+/**
+ * @typedef {number}
+ */
+var Megabit;
+
+/**
+ * @typedef {number}
+ */
+var Millisecond;
+
+/**
+ * Enum of:
+ * 'bluetooth',
+ * 'cellular',
+ * 'ethernet',
+ * 'mixed',
+ * 'none',
+ * 'other',
+ * 'unknown',
+ * 'wifi',
+ * 'wimax'
+ * @typedef {string}
+ */
+var ConnectionType;
+
+/**
+ * Enum of:
+ * '2g',
+ * '3g',
+ * '4g',
+ * 'slow-2g'
+ * @typedef {string}
+ */
+var EffectiveConnectionType;
+
+/** @type {!NetworkInformation} */
+Navigator.prototype.connection;
diff --git a/javascript/externs/web/w3c_payment_request.js b/javascript/externs/web/w3c_payment_request.js
new file mode 100644
index 000000000000..8d0aaf700b3f
--- /dev/null
+++ b/javascript/externs/web/w3c_payment_request.js
@@ -0,0 +1,401 @@
+/*
+ * Copyright 2019 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for W3C's Payment Request API.
+ * @see https://w3c.github.io/payment-request/
+ *
+ * @externs
+ */
+
+/**
+ * @constructor
+ * @param {!Array<!PaymentMethodData>} methodData
+ * @param {!PaymentDetailsInit} details
+ * @param {!PaymentOptions=} options
+ * @implements {EventTarget}
+ * @see https://w3c.github.io/payment-request/#paymentrequest-interface
+ */
+function PaymentRequest(methodData, details, options) {}
+/**
+ * @param {!Promise<!PaymentDetailsUpdate>=} detailsPromise
+ * @return {!Promise<!PaymentResponse>}
+ */
+PaymentRequest.prototype.show = function(detailsPromise) {};
+/** @return {!Promise<undefined>} */
+PaymentRequest.prototype.abort = function() {};
+/** @return {!Promise<boolean>} */
+PaymentRequest.prototype.canMakePayment = function() {};
+/** @return {!Promise<boolean>} */
+PaymentRequest.prototype.hasEnrolledInstrument = function() {};
+/** @const {string} */
+PaymentRequest.prototype.id;
+/** @const {?PaymentAddress} */
+PaymentRequest.prototype.shippingAddress;
+/** @const {?string} */
+PaymentRequest.prototype.shippingOption;
+/** @const {?string} */
+PaymentRequest.prototype.shippingType;
+/** @type {?function(!Event)} */
+PaymentRequest.prototype.onmerchantvalidation;
+/** @type {?function(!Event)} */
+PaymentRequest.prototype.onshippingaddresschange;
+/** @type {?function(!Event)} */
+PaymentRequest.prototype.onshippingoptionchange;
+/** @type {?function(!Event)} */
+PaymentRequest.prototype.onpaymentmethodchange;
+
+/**
+ * @record
+ * @see https://w3c.github.io/payment-request/#paymentmethoddata-dictionary
+ */
+function PaymentMethodData() {};
+/** @type {string} */
+PaymentMethodData.prototype.supportedMethods;
+/** @type {!Object|undefined} */
+PaymentMethodData.prototype.data;
+
+/**
+ * @record
+ * @see https://w3c.github.io/payment-request/#paymentcurrencyamount-dictionary
+ */
+function PaymentCurrencyAmount() {};
+/** @type {string} */
+PaymentCurrencyAmount.prototype.currency;
+/** @type {string} */
+PaymentCurrencyAmount.prototype.value;
+
+/**
+ * @record
+ * @see https://w3c.github.io/payment-request/#paymentdetailsbase-dictionary
+ */
+function PaymentDetailsBase() {};
+/** @type {!Array<!PaymentItem>|undefined} */
+PaymentDetailsBase.prototype.displayItems;
+/** @type {!Array<!PaymentShippingOption>|undefined} */
+PaymentDetailsBase.prototype.shippingOptions;
+/** @type {!Array<!PaymentDetailsModifier>|undefined} */
+PaymentDetailsBase.prototype.modifiers;
+
+/**
+ * @extends {PaymentDetailsBase}
+ * @record
+ * @see https://w3c.github.io/payment-request/#paymentdetailsinit-dictionary
+ */
+function PaymentDetailsInit() {};
+/** @type {string|undefined} */
+PaymentDetailsInit.prototype.id;
+/** @type {!PaymentItem} */
+PaymentDetailsInit.prototype.total;
+
+/**
+ * @extends {PaymentDetailsBase}
+ * @record
+ * @see https://w3c.github.io/payment-request/#paymentdetailsupdate-dictionary
+ */
+function PaymentDetailsUpdate() {};
+/** @type {string|undefined} */
+PaymentDetailsUpdate.prototype.error;
+/** @type {!PaymentItem|undefined} */
+PaymentDetailsUpdate.prototype.total;
+/** @type {!AddressErrors|undefined} */
+PaymentDetailsUpdate.prototype.shippingAddressErrors;
+/** @type {!PayerErrors|undefined} */
+PaymentDetailsUpdate.prototype.payerErrors;
+/** @type {!Object|undefined} */
+PaymentDetailsUpdate.prototype.paymentMethodErrors;
+
+/**
+ * @record
+ * @see https://w3c.github.io/payment-request/#paymentdetailsmodifier-dictionary
+ */
+function PaymentDetailsModifier() {};
+/** @type {string} */
+PaymentDetailsModifier.prototype.supportedMethods;
+/** @type {!PaymentItem|undefined} */
+PaymentDetailsModifier.prototype.total;
+/** @type {!Array<!PaymentItem>|undefined} */
+PaymentDetailsModifier.prototype.additionalDisplayItems;
+/** @type {!Object|undefined} */
+PaymentDetailsModifier.prototype.data;
+
+/**
+ * @record
+ * @see https://w3c.github.io/payment-request/#paymentoptions-dictionary
+ */
+function PaymentOptions() {};
+/** @type {boolean|undefined} */
+PaymentOptions.prototype.requestPayerName;
+/** @type {boolean|undefined} */
+PaymentOptions.prototype.requestBillingAddress;
+/** @type {boolean|undefined} */
+PaymentOptions.prototype.requestPayerEmail;
+/** @type {boolean|undefined} */
+PaymentOptions.prototype.requestPayerPhone;
+/** @type {boolean|undefined} */
+PaymentOptions.prototype.requestShipping;
+/** @type {string|undefined} */
+PaymentOptions.prototype.shippingType;
+
+/**
+ * @record
+ * @see https://w3c.github.io/payment-request/#paymentitem-dictionary
+ */
+function PaymentItem() {};
+/** @type {string} */
+PaymentItem.prototype.label;
+/** @type {!PaymentCurrencyAmount} */
+PaymentItem.prototype.amount;
+/** @type {boolean|undefined} */
+PaymentItem.prototype.pending;
+
+/**
+ * @interface
+ * @see https://w3c.github.io/payment-request/#paymentaddress-interface
+ */
+function PaymentAddress() {}
+/**
+ * @return {Object}
+ * @override
+ */
+PaymentAddress.prototype.toJSON = function() {};
+/** @const {string|undefined} */
+PaymentAddress.prototype.city;
+/** @const {string|undefined} */
+PaymentAddress.prototype.country;
+/** @const {string|undefined} */
+PaymentAddress.prototype.dependentLocality;
+/** @const {string|undefined} */
+PaymentAddress.prototype.organization;
+/** @const {string|undefined} */
+PaymentAddress.prototype.phone;
+/** @const {string|undefined} */
+PaymentAddress.prototype.postalCode;
+/** @const {string|undefined} */
+PaymentAddress.prototype.recipient;
+/** @const {string|undefined} */
+PaymentAddress.prototype.region;
+/** @const {string|undefined} */
+PaymentAddress.prototype.sortingCode;
+/** @const {!Array<string>|undefined} */
+PaymentAddress.prototype.addressLine;
+
+/**
+ * @record
+ * @see https://w3c.github.io/payment-request/#addressinit-dictionary
+ */
+function AddressInit() {};
+/** @type {string|undefined} */
+AddressInit.prototype.country;
+/** @type {!Array<string>|undefined} */
+AddressInit.prototype.addressLine;
+/** @type {string|undefined} */
+AddressInit.prototype.region;
+/** @type {string|undefined} */
+AddressInit.prototype.city;
+/** @type {string|undefined} */
+AddressInit.prototype.dependentLocality;
+/** @type {string|undefined} */
+AddressInit.prototype.postalCode;
+/** @type {string|undefined} */
+AddressInit.prototype.sortingCode;
+/** @type {string|undefined} */
+AddressInit.prototype.organization;
+/** @type {string|undefined} */
+AddressInit.prototype.recipient;
+/** @type {string|undefined} */
+AddressInit.prototype.phone;
+
+/**
+ * @record
+ * @see https://w3c.github.io/payment-request/#addresserrors-dictionary
+ */
+function AddressErrors() {};
+/** @type {string|undefined} */
+AddressErrors.prototype.addressLine;
+/** @type {string|undefined} */
+AddressErrors.prototype.city;
+/** @type {string|undefined} */
+AddressErrors.prototype.country;
+/** @type {string|undefined} */
+AddressErrors.prototype.dependentLocality;
+/** @type {string|undefined} */
+AddressErrors.prototype.organization;
+/** @type {string|undefined} */
+AddressErrors.prototype.phone;
+/** @type {string|undefined} */
+AddressErrors.prototype.postalCode;
+/** @type {string|undefined} */
+AddressErrors.prototype.recipient;
+/** @type {string|undefined} */
+AddressErrors.prototype.region;
+/** @type {string|undefined} */
+AddressErrors.prototype.sortingCode;
+
+/**
+ * @record
+ * @see https://w3c.github.io/payment-request/#paymentshippingoption-dictionary
+ */
+function PaymentShippingOption() {};
+/** @type {string} */
+PaymentShippingOption.prototype.id;
+/** @type {string} */
+PaymentShippingOption.prototype.label;
+/** @type {!PaymentCurrencyAmount} */
+PaymentShippingOption.prototype.amount;
+/** @type {boolean|undefined} */
+PaymentShippingOption.prototype.selected;
+
+/**
+ * @constructor
+ * @implements {EventTarget}
+ * @see https://w3c.github.io/payment-request/#paymentresponse-interface
+ */
+function PaymentResponse() {}
+/**
+ * @return {!Object}
+ * @override
+ */
+PaymentResponse.prototype.toJSON = function() {};
+/** @const {string} */
+PaymentResponse.prototype.requestId;
+/** @const {string} */
+PaymentResponse.prototype.methodName;
+/** @const {!Object} */
+PaymentResponse.prototype.details;
+/** @const {?PaymentAddress} */
+PaymentResponse.prototype.shippingAddress;
+/** @const {?string} */
+PaymentResponse.prototype.shippingOption;
+/** @const {?string} */
+PaymentResponse.prototype.payerName;
+/** @const {?string} */
+PaymentResponse.prototype.payerEmail;
+/** @const {?string} */
+PaymentResponse.prototype.payerPhone;
+/**
+ * @param {string=} result
+ * @return {!Promise<undefined>}
+ */
+PaymentResponse.prototype.complete = function(result) {};
+/**
+ * @param {!PaymentValidationErrors=} errorFields
+ * @return {!Promise<undefined>}
+ */
+PaymentResponse.prototype.retry = function(errorFields) {};
+/** @type {?function(!Event)} */
+PaymentResponse.prototype.onpayerdetailchange;
+
+/**
+ * @record
+ * @see https://w3c.github.io/payment-request/#paymentvalidationerrors-dictionary
+ */
+function PaymentValidationErrors() {};
+/** @type {!PayerErrors|undefined} */
+PaymentValidationErrors.prototype.payer;
+/** @type {!AddressErrors|undefined} */
+PaymentValidationErrors.prototype.shippingAddress;
+/** @type {string|undefined} */
+PaymentValidationErrors.prototype.error;
+/** @type {!Object|undefined} */
+PaymentValidationErrors.prototype.paymentMethod;
+
+/**
+ * @record
+ * @see https://w3c.github.io/payment-request/#payererrors-dictionary
+ */
+function PayerErrors() {};
+/** @type {string|undefined} */
+PayerErrors.prototype.email;
+/** @type {string|undefined} */
+PayerErrors.prototype.name;
+/** @type {string|undefined} */
+PayerErrors.prototype.phone;
+
+/**
+ * @constructor
+ * @param {string} type
+ * @param {!MerchantValidationEventInit=} eventInitDict
+ * @extends {Event}
+ * @see https://w3c.github.io/payment-request/#merchantvalidationevent-interface
+ */
+function MerchantValidationEvent(type, eventInitDict) {};
+/** @const {string} */
+MerchantValidationEvent.prototype.methodName;
+/** @const {string} */
+MerchantValidationEvent.prototype.validationURL;
+/**
+ * @param {!Promise<undefined>} merchantSessionPromise
+ * @return {undefined}
+ */
+MerchantValidationEvent.prototype.complete = function(
+    merchantSessionPromise) {};
+
+/**
+ * @extends {EventInit}
+ * @record
+ * @see https://w3c.github.io/payment-request/#merchantvalidationeventinit-dictionary
+ */
+function MerchantValidationEventInit() {};
+/** @type {string|undefined} */
+MerchantValidationEventInit.prototype.methodName;
+/** @type {string|undefined} */
+MerchantValidationEventInit.prototype.validationURL;
+
+/**
+ * @constructor
+ * @param {string} type
+ * @param {!PaymentMethodChangeEventInit=} eventInitDict
+ * @extends {PaymentRequestUpdateEvent}
+ * @see https://w3c.github.io/payment-request/#paymentmethodchangeevent-interface
+ */
+function PaymentMethodChangeEvent(type, eventInitDict) {};
+/** @const {string} */
+PaymentMethodChangeEvent.prototype.methodName;
+/** @const {?Object} */
+PaymentMethodChangeEvent.prototype.methodDetails;
+
+/**
+ * @extends {PaymentRequestUpdateEventInit}
+ * @record
+ * @see https://w3c.github.io/payment-request/#paymentmethodchangeeventinit-dictionary
+ */
+function PaymentMethodChangeEventInit() {};
+/** @type {string|undefined} */
+PaymentMethodChangeEventInit.prototype.methodName;
+/** @type {?Object|undefined} */
+PaymentMethodChangeEventInit.prototype.methodDetails;
+
+/**
+ * @constructor
+ * @param {string} type
+ * @param {!PaymentRequestUpdateEventInit=} eventInitDict
+ * @extends {Event}
+ * @see https://w3c.github.io/payment-request/#paymentrequestupdateevent-interface
+ */
+function PaymentRequestUpdateEvent(type, eventInitDict) {};
+/**
+ * @param {!Promise<!PaymentDetailsUpdate>} detailsPromise
+ * @return {undefined}
+ */
+PaymentRequestUpdateEvent.prototype.updateWith = function(detailsPromise) {};
+
+/**
+ * @extends {EventInit}
+ * @record
+ * @see https://w3c.github.io/payment-request/#paymentrequestupdateeventinit-dictionary
+ */
+function PaymentRequestUpdateEventInit() {};
diff --git a/javascript/externs/web/w3c_pointerlock.js b/javascript/externs/web/w3c_pointerlock.js
new file mode 100644
index 000000000000..e233acfebfb5
--- /dev/null
+++ b/javascript/externs/web/w3c_pointerlock.js
@@ -0,0 +1,63 @@
+/*
+ * Copyright 2015 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for W3C's Pointer Lock API.
+ * @see https://w3c.github.io/pointerlock/
+ *
+ * @externs
+ */
+
+/**
+ * TODO(bradfordcsmith): update the link when PR is merged
+ * @see https://github.com/w3c/pointerlock/pull/49/
+ * @record
+ */
+function PointerLockOptions() {}
+
+/** @type {undefined|boolean} */
+PointerLockOptions.prototype.unadjustedMovement;
+
+/**
+ * @see https://w3c.github.io/pointerlock/#widl-Element-requestPointerLock-void
+ * @param {!PointerLockOptions=} options
+ * @return {void|!Promise<void>}
+ */
+Element.prototype.requestPointerLock = function(options) {};
+
+/**
+ * @see https://w3c.github.io/pointerlock/#widl-Document-pointerLockElement
+ * @type {?Element}
+ */
+Document.prototype.pointerLockElement;
+
+/**
+ * @see https://w3c.github.io/pointerlock/#widl-Document-exitPointerLock-void
+ * @return {void}
+ */
+Document.prototype.exitPointerLock = function() {};
+
+/**
+ * @see https://w3c.github.io/pointerlock/#widl-MouseEvent-movementX
+ * @type {number}
+ */
+MouseEvent.prototype.movementX;
+
+/**
+ * @see https://w3c.github.io/pointerlock/#widl-MouseEvent-movementY
+ * @type {number}
+ */
+MouseEvent.prototype.movementY;
diff --git a/javascript/externs/web/w3c_referrer_policy.js b/javascript/externs/web/w3c_referrer_policy.js
new file mode 100644
index 000000000000..3b2509ca69ef
--- /dev/null
+++ b/javascript/externs/web/w3c_referrer_policy.js
@@ -0,0 +1,36 @@
+/*
+ * Copyright 2018 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for W3C's referrer policy specification.
+ * @see https://w3c.github.io/webappsec-referrer-policy/#referrer-policy-delivery
+ * @externs
+ */
+
+/** @type {string} */
+HTMLAnchorElement.prototype.referrerPolicy;
+
+/** @type {string} */
+HTMLAreaElement.prototype.referrerPolicy;
+
+/** @type {string} */
+HTMLImageElement.prototype.referrerPolicy;
+
+/** @type {string} */
+HTMLIFrameElement.prototype.referrerPolicy;
+
+/** @type {string} */
+HTMLLinkElement.prototype.referrerPolicy;
diff --git a/javascript/externs/web/w3c_screen_wake_lock.js b/javascript/externs/web/w3c_screen_wake_lock.js
new file mode 100644
index 000000000000..20e9884230cd
--- /dev/null
+++ b/javascript/externs/web/w3c_screen_wake_lock.js
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2020 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/**
+ * Screen Wake Lock API
+ * W3C Editor's Draft 01 September 2020
+ * @externs
+ * @see https://w3c.github.io/screen-wake-lock/
+ */
+
+
+/** @type {!WakeLock} */
+Navigator.prototype.wakeLock;
+
+
+/**
+ * @interface
+ * @see https://w3c.github.io/screen-wake-lock/#the-wakelock-interface
+ */
+function WakeLock() {};
+
+/**
+ * @param {string} type
+ * @return {!Promise<!WakeLockSentinel>}
+ */
+WakeLock.prototype.request = function(type) {};
+
+
+/**
+ * @interface
+ * @extends {EventTarget}
+ * @see https://w3c.github.io/screen-wake-lock/#the-wakelocksentinel-interface
+ */
+function WakeLockSentinel() {};
+
+/** @type {?function(!Event)} */
+WakeLockSentinel.prototype.onrelease;
+
+/** @return {!Promise<void>} */
+WakeLockSentinel.prototype.release = function() {};
+
+/** @type {boolean} @const */
+WakeLockSentinel.prototype.released;
+
+/** @type {string} @const */
+WakeLockSentinel.prototype.type;
diff --git a/javascript/externs/web/w3c_selection.js b/javascript/externs/web/w3c_selection.js
new file mode 100644
index 000000000000..36993c7127b6
--- /dev/null
+++ b/javascript/externs/web/w3c_selection.js
@@ -0,0 +1,209 @@
+/*
+ * Copyright 2008 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for W3C's Selection API.
+ *
+ * @see https://w3c.github.io/selection-api/
+ *
+ * @externs
+ */
+
+/**
+ * @constructor
+ * @see http://w3c.github.io/selection-api/#selection-interface
+ */
+function Selection() {}
+
+/**
+ * @type {?Node}
+ * @see https://w3c.github.io/selection-api/#dom-selection-anchornode
+ */
+Selection.prototype.anchorNode;
+
+/**
+ * @type {number}
+ * @see https://w3c.github.io/selection-api/#dom-selection-anchoroffset
+ */
+Selection.prototype.anchorOffset;
+
+/**
+ * @type {?Node}
+ * @see https://w3c.github.io/selection-api/#dom-selection-focusnode
+ */
+Selection.prototype.focusNode;
+
+/**
+ * @type {number}
+ * @see https://w3c.github.io/selection-api/#dom-selection-focusoffset
+ */
+Selection.prototype.focusOffset;
+
+/**
+ * @type {boolean}
+ * @see https://w3c.github.io/selection-api/#dom-selection-iscollapsed
+ */
+Selection.prototype.isCollapsed;
+
+/**
+ * @type {number}
+ * @see https://w3c.github.io/selection-api/#dom-selection-rangecount
+ */
+Selection.prototype.rangeCount;
+
+/**
+ * @type {string}
+ * @see https://w3c.github.io/selection-api/#dom-selection-type
+ */
+Selection.prototype.type;
+
+/**
+ * @param {number} index
+ * @return {!Range}
+ * @nosideeffects
+ * @see https://w3c.github.io/selection-api/#dom-selection-getrangeat
+ */
+Selection.prototype.getRangeAt = function(index) {};
+
+/**
+ * TODO(tjgq): Clean up internal usages and make the `range` parameter a
+ * `!Range` per the spec.
+ * @param {?Range} range
+ * @return {undefined}
+ * @see https://w3c.github.io/selection-api/#dom-selection-addrange
+ */
+Selection.prototype.addRange = function(range) {};
+
+/**
+ * @param {!Range} range
+ * @return {undefined}
+ * @see https://w3c.github.io/selection-api/#dom-selection-removerange
+ */
+Selection.prototype.removeRange = function(range) {};
+
+/**
+ * @return {undefined}
+ * @see https://w3c.github.io/selection-api/#dom-selection-removeallranges
+ */
+Selection.prototype.removeAllRanges = function() {};
+
+/**
+ * @return {undefined}
+ * @see https://w3c.github.io/selection-api/#dom-selection-empty
+ */
+Selection.prototype.empty = function() {};
+
+/**
+ * @param {?Node} node
+ * @param {number=} offset
+ * @return {undefined}
+ * @see https://w3c.github.io/selection-api/#dom-selection-collapse
+ */
+Selection.prototype.collapse = function(node, offset) {};
+
+/**
+ * @param {?Node} node
+ * @param {number=} offset
+ * @return {undefined}
+ * @see https://w3c.github.io/selection-api/#dom-selection-setposition
+ */
+Selection.prototype.setPosition = function(node, offset) {};
+
+/**
+ * @return {undefined}
+ * @see https://w3c.github.io/selection-api/#dom-selection-collapsetostart
+ */
+Selection.prototype.collapseToStart = function() {};
+
+/**
+ * @return {undefined}
+ * @see https://w3c.github.io/selection-api/#dom-selection-collapsetoend
+ */
+Selection.prototype.collapseToEnd = function() {};
+
+/**
+ * TODO(tjgq): Clean up internal usages and make the `node` parameter a `!Node`
+ * per the spec.
+ * @param {?Node} node
+ * @param {number=} offset
+ * @return {undefined}
+ * @see https://w3c.github.io/selection-api/#dom-selection-extend
+ */
+Selection.prototype.extend = function(node, offset) {};
+
+/**
+ * TODO(tjgq): Clean up internal usages and make the `anchorNode` and
+ * `focusNode` parameters `!Node` per the spec.
+ * @param {?Node} anchorNode
+ * @param {number} anchorOffset
+ * @param {?Node} focusNode
+ * @param {number} focusOffset
+ * @return {undefined}
+ * @see https://w3c.github.io/selection-api/#dom-selection-setbaseandextent
+ */
+Selection.prototype.setBaseAndExtent = function(anchorNode, anchorOffset, focusNode, focusOffset) {};
+
+/**
+ * TODO(tjgq): Clean up internal usages and make the `node` parameter a `!Node`
+ * per the spec.
+ * @param {?Node} node
+ * @return {undefined}
+ * @see http://w3c.github.io/selection-api/#dom-selection-selectallchildren
+ */
+Selection.prototype.selectAllChildren = function(node) {};
+
+/**
+ * @return {undefined}
+ * @see https://w3c.github.io/selection-api/#dom-selection-deletefromdocument
+ */
+Selection.prototype.deleteFromDocument = function() {};
+
+/**
+ * @param {!Node} node
+ * @param {boolean=} allowPartialContainment
+ * @return {boolean}
+ * @nosideeffects
+ * @see https://w3c.github.io/selection-api/#dom-selection-containsnode
+ */
+Selection.prototype.containsNode = function(node, allowPartialContainment) {};
+
+/**
+ * @return {?Selection}
+ * @nosideeffects
+ * @see https://w3c.github.io/selection-api/#dom-window-getselection
+ */
+Window.prototype.getSelection = function() {};
+
+/**
+ * @return {?Selection}
+ * @nosideeffects
+ * @see https://w3c.github.io/selection-api/#dom-document-getselection
+ */
+Document.prototype.getSelection = function() {};
+
+/**
+ * TODO(tjgq): Clean up internal usages and make this `?function(!Event): void`
+ * per the spec.
+ * @type {?function(?Event)}
+ * @see https://w3c.github.io/selection-api/#dom-globaleventhandlers-onselectstart
+ */
+Element.prototype.onselectstart;
+
+/**
+ * @type {?function(!Event): void}
+ * @see https://w3c.github.io/selection-api/#dom-globaleventhandlers-onselectionchange
+ */
+Element.prototype.onselectionchange;
diff --git a/javascript/externs/web/w3c_speech.js b/javascript/externs/web/w3c_speech.js
new file mode 100644
index 000000000000..898eb98064f2
--- /dev/null
+++ b/javascript/externs/web/w3c_speech.js
@@ -0,0 +1,412 @@
+/*
+ * Copyright 2011 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for W3C's Speech Input 2010 draft API and the
+ * 2012 Web Speech draft API (in progress).
+ * 2010 Speech Input API:
+ * http://www.w3.org/2005/Incubator/htmlspeech/2010/10/google-api-draft.html
+ * 2012 Web Speech API:
+ * http://dvcs.w3.org/hg/speech-api/raw-file/tip/speechapi.html
+ * This file contains only those functions/properties that are actively
+ * used in the Voice Search experiment. Because the draft is under discussion
+ * and constantly evolving, this file does not attempt to stay in sync with it.
+ *
+ * @externs
+ */
+
+// W3C Speech Input API implemented in Chrome M12
+/**
+ * @constructor
+ * @extends {UIEvent}
+ */
+function SpeechInputEvent() {}
+
+/** @type {SpeechInputResultList} */
+SpeechInputEvent.prototype.results;
+
+
+/**
+ * @constructor
+ */
+function SpeechInputResultList() {}
+
+/** @type {number} */
+SpeechInputResultList.prototype.length;
+
+
+/**
+ * @constructor
+ */
+function SpeechInputResult() {}
+
+/** @type {string} */
+SpeechInputResult.prototype.utterance;
+
+/** @type {number} */
+SpeechInputResult.prototype.confidence;
+
+
+// HTMLInputElement
+/** @type {boolean} */
+HTMLInputElement.prototype.webkitspeech;
+
+/** @type {?function (Event)} */
+HTMLInputElement.prototype.onwebkitspeechchange;
+
+
+
+// W3C Web Speech API implemented in Chrome M23
+/**
+ * @constructor
+ * @implements {EventTarget}
+ */
+function SpeechRecognition() {}
+
+/** @override */
+SpeechRecognition.prototype.addEventListener = function(
+    type, listener, opt_options) {};
+
+/** @override */
+SpeechRecognition.prototype.removeEventListener = function(
+    type, listener, opt_options) {};
+
+/** @override */
+SpeechRecognition.prototype.dispatchEvent = function(evt) {};
+
+/** @type {SpeechGrammarList} */
+SpeechRecognition.prototype.grammars;
+
+/** @type {string} */
+SpeechRecognition.prototype.lang;
+
+/** @type {boolean} */
+SpeechRecognition.prototype.continuous;
+
+/** @type {boolean} */
+SpeechRecognition.prototype.interimResults;
+
+/** @type {number} */
+SpeechRecognition.prototype.maxAlternatives;
+
+/** @type {string} */
+SpeechRecognition.prototype.serviceURI;
+
+/** @type {function()} */
+SpeechRecognition.prototype.start;
+
+/** @type {function()} */
+SpeechRecognition.prototype.stop;
+
+/** @type {function()} */
+SpeechRecognition.prototype.abort;
+
+/** @type {?function(!Event)} */
+SpeechRecognition.prototype.onaudiostart;
+
+/** @type {?function(!Event)} */
+SpeechRecognition.prototype.onsoundstart;
+
+/** @type {?function(!Event)} */
+SpeechRecognition.prototype.onspeechstart;
+
+/** @type {?function(!Event)} */
+SpeechRecognition.prototype.onspeechend;
+
+/** @type {?function(!Event)} */
+SpeechRecognition.prototype.onsoundend;
+
+/** @type {?function(!Event)} */
+SpeechRecognition.prototype.onaudioend;
+
+/** @type {?function(!SpeechRecognitionEvent)} */
+SpeechRecognition.prototype.onresult;
+
+/** @type {?function(!SpeechRecognitionEvent)} */
+SpeechRecognition.prototype.onnomatch;
+
+/** @type {?function(!SpeechRecognitionError)} */
+SpeechRecognition.prototype.onerror;
+
+/** @type {?function(!Event)} */
+SpeechRecognition.prototype.onstart;
+
+/** @type {?function(!Event)} */
+SpeechRecognition.prototype.onend;
+
+
+/**
+ * @constructor
+ * @extends {Event}
+ */
+function SpeechRecognitionError() {}
+
+/** @type {string} */
+SpeechRecognitionError.prototype.error;
+
+/** @type {string} */
+SpeechRecognitionError.prototype.message;
+
+
+/**
+ * @constructor
+ */
+function SpeechRecognitionAlternative() {}
+
+/** @type {string} */
+SpeechRecognitionAlternative.prototype.transcript;
+
+/** @type {number} */
+SpeechRecognitionAlternative.prototype.confidence;
+
+
+/**
+ * @constructor
+ */
+function SpeechRecognitionResult() {}
+
+/**
+ * @type {number}
+ */
+SpeechRecognitionResult.prototype.length;
+
+/**
+ * @type {function(number): SpeechRecognitionAlternative}
+ */
+SpeechRecognitionResult.prototype.item = function(index) {};
+
+/**
+ * @type {boolean}
+ */
+SpeechRecognitionResult.prototype.isFinal;
+
+
+/**
+ * @constructor
+ */
+function SpeechRecognitionResultList() {}
+
+/**
+ * @type {number}
+ */
+SpeechRecognitionResultList.prototype.length;
+
+/**
+ * @type {function(number): SpeechRecognitionResult}
+ */
+SpeechRecognitionResultList.prototype.item = function(index) {};
+
+
+/**
+ * @constructor
+ * @extends {Event}
+ */
+function SpeechRecognitionEvent() {}
+
+/** @type {number} */
+SpeechRecognitionEvent.prototype.resultIndex;
+
+/** @type {SpeechRecognitionResultList} */
+SpeechRecognitionEvent.prototype.results;
+
+/** @type {*} */
+SpeechRecognitionEvent.prototype.interpretation;
+
+/** @type {Document} */
+SpeechRecognitionEvent.prototype.emma;
+
+
+/**
+ * @constructor
+ */
+function SpeechGrammar() {}
+
+/** @type {string} */
+SpeechGrammar.prototype.src;
+
+/** @type {number} */
+SpeechGrammar.prototype.weight;
+
+
+/**
+ * @constructor
+ */
+function SpeechGrammarList() {}
+
+/**
+ * @type {number}
+ */
+SpeechGrammarList.prototype.length;
+
+/**
+ * @type {function(number): SpeechGrammar}
+ */
+SpeechGrammarList.prototype.item = function(index) {};
+
+/**
+ * @type {function(string, number)}
+ */
+SpeechGrammarList.prototype.addFromUri = function(src, weight) {};
+
+/**
+ * @type {function(string, number)}
+ */
+SpeechGrammarList.prototype.addFromString = function(str, weight) {};
+
+
+// Webkit implementations of Web Speech API
+/**
+ * @constructor
+ * @extends {SpeechGrammarList}
+ */
+function webkitSpeechGrammarList() {}
+
+
+/**
+ * @constructor
+ * @extends {SpeechGrammar}
+ */
+function webkitSpeechGrammar() {}
+
+
+/**
+ * @constructor
+ * @extends {SpeechRecognitionEvent}
+ */
+function webkitSpeechRecognitionEvent() {}
+
+
+/**
+ * @constructor
+ * @extends {SpeechRecognitionError}
+ */
+function webkitSpeechRecognitionError() {}
+
+
+/**
+ * @constructor
+ * @extends {SpeechRecognition}
+ */
+function webkitSpeechRecognition() {}
+
+
+
+// W3C Web Speech Synthesis API is implemented in Chrome M33
+/**
+ * @type {SpeechSynthesis}
+ * @see https://dvcs.w3.org/hg/speech-api/raw-file/tip/speechapi.html#tts-section
+ */
+var speechSynthesis;
+
+
+/**
+ * @constructor
+ * @param {string} text
+ */
+function SpeechSynthesisUtterance(text) {}
+
+/** @type {string} */
+SpeechSynthesisUtterance.prototype.text;
+
+/** @type {string} */
+SpeechSynthesisUtterance.prototype.lang;
+
+/** @type {number} */
+SpeechSynthesisUtterance.prototype.pitch;
+
+/** @type {number} */
+SpeechSynthesisUtterance.prototype.rate;
+
+/** @type {SpeechSynthesisVoice} */
+SpeechSynthesisUtterance.prototype.voice;
+
+/** @type {number} */
+SpeechSynthesisUtterance.prototype.volume;
+
+/**
+ * @param {Event} event
+ */
+SpeechSynthesisUtterance.prototype.onstart = function(event) {};
+
+/**
+ * @param {Event} event
+ */
+SpeechSynthesisUtterance.prototype.onend = function(event) {};
+
+/**
+ * @param {Event} event
+ */
+SpeechSynthesisUtterance.prototype.onerror = function(event) {};
+
+/**
+ * @constructor
+ */
+function SpeechSynthesisVoice() {}
+
+/** @type {string} */
+SpeechSynthesisVoice.prototype.voiceURI;
+
+/** @type {string} */
+SpeechSynthesisVoice.prototype.name;
+
+/** @type {string} */
+SpeechSynthesisVoice.prototype.lang;
+
+/** @type {boolean} */
+SpeechSynthesisVoice.prototype.localService;
+
+/** @type {boolean} */
+SpeechSynthesisVoice.prototype.default;
+
+
+/**
+ * @constructor
+ * @extends {Array<!SpeechSynthesisVoice>}
+ */
+function SpeechSynthesisVoiceList() {}
+
+
+/**
+ * @interface
+ * @extends {EventTarget}
+ */
+function SpeechSynthesis() {}
+
+/**
+ * @param {SpeechSynthesisUtterance} utterance
+ * @return {undefined}
+ */
+SpeechSynthesis.prototype.speak = function(utterance) {};
+
+/** @type {function()} */
+SpeechSynthesis.prototype.cancel;
+
+/** @type {function()} */
+SpeechSynthesis.prototype.pause;
+
+/** @type {function()} */
+SpeechSynthesis.prototype.resume;
+
+/**
+ * @return {SpeechSynthesisVoiceList}
+ */
+SpeechSynthesis.prototype.getVoices = function() {};
+
+/**
+ * @param {Event} event
+ * @see https://dvcs.w3.org/hg/speech-api/raw-file/tip/speechapi-errata.html
+ */
+SpeechSynthesis.prototype.onvoiceschanged = function(event) {};
diff --git a/javascript/externs/web/w3c_trusted_types.js b/javascript/externs/web/w3c_trusted_types.js
new file mode 100644
index 000000000000..a27409bc5bca
--- /dev/null
+++ b/javascript/externs/web/w3c_trusted_types.js
@@ -0,0 +1,139 @@
+/*
+ * Copyright 2018 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for W3C's Trusted Types specification.
+ * @see https://w3c.github.io/webappsec-trusted-types/dist/spec/
+ * @externs
+ */
+
+
+/** @constructor */
+function TrustedHTML() {}
+
+// function TrustedScript() was moved to `es3.js` so that is could be used by
+// `eval()`.
+
+/** @constructor */
+function TrustedScriptURL() {}
+
+
+/**
+ * @template Options
+ * @constructor
+ */
+function TrustedTypePolicy() {}
+
+/**
+ * @param {string} s
+ * @return {!TrustedHTML}
+ */
+TrustedTypePolicy.prototype.createHTML = function(s) {};
+
+/**
+ * @param {string} s
+ * @return {!TrustedScript}
+ */
+TrustedTypePolicy.prototype.createScript = function(s) {};
+
+/**
+ * @param {string} s
+ * @return {!TrustedScriptURL}
+ */
+TrustedTypePolicy.prototype.createScriptURL = function(s) {};
+
+
+/** @constructor */
+function TrustedTypePolicyFactory() {}
+
+/** @record @private */
+function TrustedTypePolicyOptions() {};
+
+/**
+ *  @type {(function(string, ...*): string)|undefined},
+ */
+TrustedTypePolicyOptions.prototype.createHTML;
+
+/**
+ *  @type {(function(string, ...*): string)|undefined},
+ */
+TrustedTypePolicyOptions.prototype.createScript;
+
+/**
+ *  @type {(function(string, ...*): string)|undefined},
+ */
+TrustedTypePolicyOptions.prototype.createScriptURL;
+
+
+/**
+ * @param {string} name
+ * @param {!TrustedTypePolicyOptions} policy
+ * @return {!TrustedTypePolicy}
+ */
+TrustedTypePolicyFactory.prototype.createPolicy = function(name, policy) {};
+
+
+/**
+ * @param {*} obj
+ * @return {boolean}
+ */
+TrustedTypePolicyFactory.prototype.isHTML = function(obj) {};
+
+/**
+ * @param {*} obj
+ * @return {boolean}
+ */
+TrustedTypePolicyFactory.prototype.isScript = function(obj) {};
+
+/**
+ * @param {*} obj
+ * @return {boolean}
+ */
+TrustedTypePolicyFactory.prototype.isScriptURL = function(obj) {};
+
+
+/** @type {!TrustedHTML} */
+TrustedTypePolicyFactory.prototype.emptyHTML;
+
+
+/** @type {!TrustedScript} */
+TrustedTypePolicyFactory.prototype.emptyScript;
+
+/**
+ * @param {string} tagName
+ * @param {string} attribute
+ * @param {string=} elementNs
+ * @param {string=} attrNs
+ * @return {?string}
+ */
+TrustedTypePolicyFactory.prototype.getAttributeType = function(
+    tagName, attribute, elementNs, attrNs) {};
+
+/**
+ * @param {string} tagName
+ * @param {string} property
+ * @param {string=} elementNs
+ * @return {?string}
+ */
+TrustedTypePolicyFactory.prototype.getPropertyType = function(
+    tagName, property, elementNs) {};
+
+/** @type {?TrustedTypePolicy} */
+TrustedTypePolicyFactory.prototype.defaultPolicy;
+
+
+/** @type {!TrustedTypePolicyFactory} */
+var trustedTypes;
diff --git a/javascript/externs/web/w3c_vibration.js b/javascript/externs/web/w3c_vibration.js
new file mode 100644
index 000000000000..e30db412ed2f
--- /dev/null
+++ b/javascript/externs/web/w3c_vibration.js
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2017 The Closure Compiler Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for Vibration API based on "W3C Recommendation 18 October 2016"
+ * @see https://www.w3.org/TR/2016/REC-vibration-20161018/
+ *
+ * @externs
+ * @author vobruba.martin@gmail.com (Martin Vobruba)
+ */
+
+
+/**
+ * @typedef {number|!Array<number>}
+ * @see https://www.w3.org/TR/2016/REC-vibration-20161018/#idl-def-vibratepattern
+ */
+var VibratePattern;
+
+
+/**
+ * @param {!VibratePattern} pattern
+ * @return {boolean}
+ * @see https://www.w3.org/TR/2016/REC-vibration-20161018/#idl-def-navigator-vibrate(vibratepattern)
+ */
+Navigator.prototype.vibrate = function(pattern) {};
diff --git a/javascript/externs/web/w3c_worklets.js b/javascript/externs/web/w3c_worklets.js
new file mode 100644
index 000000000000..3ac54f5fadf7
--- /dev/null
+++ b/javascript/externs/web/w3c_worklets.js
@@ -0,0 +1,54 @@
+/*
+ * Copyright 2020 The Closure Compiler Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for the Worklets API.
+ * This file is based on the W3C Editor's Draft 07 April 2020.
+ * @see https://drafts.css-houdini.org/worklets/
+ *
+ * @externs
+ */
+
+/**
+ * @interface
+ * @see https://drafts.css-houdini.org/worklets/#the-global-scope
+ */
+function WorkletGlobalScope() {}
+
+/**
+ * @record
+ * @see https://drafts.css-houdini.org/worklets/#dictdef-workletoptions
+ */
+function WorkletOptions() {};
+
+/**
+ * @type {!RequestCredentials}
+ * See https://fetch.spec.whatwg.org/#requestcredentials for valid values.
+ */
+WorkletOptions.prototype.credentials;
+
+/**
+ * @interface
+ * @see https://drafts.css-houdini.org/worklets/#worklet-section
+ */
+function Worklet() {}
+
+/**
+ * @param {string} moduleURL
+ * @param {!WorkletOptions=} options
+ * @return {!Promise<void>}
+ */
+Worklet.prototype.addModule = function(moduleURL, options) {};
diff --git a/javascript/externs/web/web_animations.js b/javascript/externs/web/web_animations.js
new file mode 100644
index 000000000000..b2c23b556d3f
--- /dev/null
+++ b/javascript/externs/web/web_animations.js
@@ -0,0 +1,362 @@
+/*
+ * Copyright 2016 The Closure Compiler authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+/**
+ * @fileoverview Basic externs for the Web Animations API. This is not
+ * nessecarily exhaustive. For more information, see the spec-
+ *   https://w3c.github.io/web-animations
+ * @externs
+ */
+
+
+/**
+ * @param {!Object} frames
+ * @param {(number|KeyframeAnimationOptions)=} options
+ * @return {!Animation}
+ * @see https://www.w3.org/TR/web-animations/#the-animatable-interface-mixin
+ */
+Element.prototype.animate = function(frames, options) {};
+
+/**
+ * @return {!Array<!Animation>}
+ */
+Element.prototype.getAnimations = function() {};
+
+
+/**
+ * @constructor
+ * @param {?AnimationEffect=} effect
+ * @param {AnimationTimeline=} timeline
+ * @implements {EventTarget}
+ */
+var Animation = function(effect, timeline) {};
+
+/** @override */
+Animation.prototype.addEventListener = function(type, listener, options) {};
+
+/** @override */
+Animation.prototype.removeEventListener = function(type, listener, options) {};
+
+/** @override */
+Animation.prototype.dispatchEvent = function(evt) {};
+
+/**
+ * @return {undefined}
+ */
+Animation.prototype.cancel = function() {};
+
+/**
+ * @return {undefined}
+ */
+Animation.prototype.finish = function() {};
+
+/**
+ * @return {undefined}
+ */
+Animation.prototype.pause = function() {};
+
+/**
+ * @return {undefined}
+ */
+Animation.prototype.play = function() {};
+
+/**
+ * @return {undefined}
+ */
+Animation.prototype.reverse = function() {};
+
+/** @type {number} */
+Animation.prototype.currentTime;
+
+/** @type {?AnimationEffect} */
+Animation.prototype.effect;
+
+/** @type {!Promise<void>} */
+Animation.prototype.finished;
+
+/** @type {string} */
+Animation.prototype.id;
+
+/** @type {?function(!Event)} */
+Animation.prototype.oncancel;
+
+/** @type {?function(!Event)} */
+Animation.prototype.onfinish;
+
+/** @type {number} */
+Animation.prototype.playbackRate;
+
+/** @type {string} */
+Animation.prototype.playState;
+
+/** @type {!Promise<void>} */
+Animation.prototype.ready;
+
+/** @type {number} */
+Animation.prototype.startTime;
+
+/** @type {!AnimationTimeline} */
+Animation.prototype.timeline;
+
+
+/**
+ * @interface
+ */
+var AnimationEffect = function() {};
+
+/**
+ * @return {!ComputedTimingProperties}
+ */
+AnimationEffect.prototype.getComputedTiming = function() {};
+
+/** @param {AnimationEffectTimingProperties=} timing */
+AnimationEffect.prototype.updateTiming = function(timing) {};
+
+/** @type {!AnimationEffectTiming} */
+AnimationEffect.prototype.timing;
+
+/**
+ * @constructor
+ * @param {Element} target
+ * @param {(!Array<!Object<string, *>>|!Object<string, !Array<*>>)} frames
+ * @param {(number|AnimationEffectTimingProperties)=} options
+ * @implements {AnimationEffect}
+ */
+var KeyframeEffectReadOnly = function(target, frames, options) {};
+
+/** @override */
+KeyframeEffectReadOnly.prototype.getComputedTiming = function() {};
+
+/** @override */
+KeyframeEffectReadOnly.prototype.timing;
+
+
+/**
+ * @constructor
+ * @param {Element} target
+ * @param {(!Array<!Object<string, *>>|!Object<string, !Array<*>>)} frames
+ * @param {(number|AnimationEffectTimingProperties)=} options
+ * @extends {KeyframeEffectReadOnly}
+ */
+var KeyframeEffect = function(target, frames, options) {};
+
+
+/**
+ * @record
+ */
+var AnimationEffectTimingProperties = function() {};
+
+/** @type {number|undefined} */
+AnimationEffectTimingProperties.prototype.delay;
+
+/** @type {number|undefined} */
+AnimationEffectTimingProperties.prototype.endDelay;
+
+/** @type {string|undefined} */
+AnimationEffectTimingProperties.prototype.fill;
+
+/** @type {number|undefined} */
+AnimationEffectTimingProperties.prototype.iterationStart;
+
+/** @type {number|undefined} */
+AnimationEffectTimingProperties.prototype.iterations;
+
+/** @type {number|string|undefined} */
+AnimationEffectTimingProperties.prototype.duration;
+
+/** @type {string|undefined} */
+AnimationEffectTimingProperties.prototype.direction;
+
+/** @type {string|undefined} */
+AnimationEffectTimingProperties.prototype.easing;
+
+/**
+ * @record
+ * @extends {AnimationEffectTimingProperties}
+ */
+var KeyframeEffectOptions = function() {};
+
+/**
+ * Possible values: 'replace', 'accumulate'
+ * @type {string|undefined}
+ */
+KeyframeEffectOptions.prototype.iterationComposite;
+
+/**
+ * Possible values: 'replace', 'add', 'accumulate'
+ * @type {string|undefined}
+ */
+KeyframeEffectOptions.prototype.composite;
+
+/**
+ * @record
+ * @extends {KeyframeEffectOptions}
+ */
+var KeyframeAnimationOptions = function() {};
+
+/** @type {string|undefined} */
+KeyframeAnimationOptions.prototype.id;
+
+
+/**
+ * @record
+ * @extends {AnimationEffectTimingProperties}
+ */
+var ComputedTimingProperties = function() {};
+
+/** @type {number} */
+ComputedTimingProperties.prototype.endTime;
+
+/** @type {number} */
+ComputedTimingProperties.prototype.activeDuration;
+
+/** @type {?number} */
+ComputedTimingProperties.prototype.localTime;
+
+/** @type {?number} */
+ComputedTimingProperties.prototype.progress;
+
+/** @type {?number} */
+ComputedTimingProperties.prototype.currentIteration;
+
+
+/**
+ * @interface
+ */
+var AnimationEffectTimingReadOnly = function() {};
+
+/** @type {number} */
+AnimationEffectTimingReadOnly.prototype.delay;
+
+/** @type {number} */
+AnimationEffectTimingReadOnly.prototype.endDelay;
+
+/** @type {string} */
+AnimationEffectTimingReadOnly.prototype.fill;
+
+/** @type {number} */
+AnimationEffectTimingReadOnly.prototype.iterationStart;
+
+/** @type {number} */
+AnimationEffectTimingReadOnly.prototype.iterations;
+
+/** @type {number|string} */
+AnimationEffectTimingReadOnly.prototype.duration;
+
+/** @type {string} */
+AnimationEffectTimingReadOnly.prototype.direction;
+
+/** @type {string} */
+AnimationEffectTimingReadOnly.prototype.easing;
+
+
+/**
+ * @interface
+ * @extends {AnimationEffectTimingReadOnly}
+ */
+var AnimationEffectTiming = function() {};
+
+
+/**
+ * @interface
+ */
+var AnimationTimeline = function() {};
+
+/** @type {?number} */
+AnimationTimeline.prototype.currentTime;
+
+
+/**
+ * @constructor
+ * @implements {AnimationTimeline}
+ */
+var DocumentTimeline = function() {};
+
+/** @override */
+DocumentTimeline.prototype.currentTime;
+
+
+/** @type {!DocumentTimeline} */
+Document.prototype.timeline;
+
+/**
+ * Externs for the Web Animations API (Level 2 / Groups).
+ *
+ * This defines externs for the "-next" version of the Web Animations API
+ * polyfill found online at:
+ *    https://github.com/web-animations/web-animations.js
+ *
+ * These features are NOT natively implemented in browsers and are not clearly
+ * part of the official spec. This is NOT intended to be exhaustive, and
+ * requires the base externs from web-animations.js.
+ *
+ */
+
+
+/** @type {Element} */
+KeyframeEffectReadOnly.prototype.target;
+
+/** @type {?function(number, !KeyframeEffect, !Animation)|undefined} */
+KeyframeEffectReadOnly.prototype.onsample;
+
+
+/**
+ * @param {!AnimationEffect} effect
+ * @return {!Animation}
+ */
+DocumentTimeline.prototype.play = function(effect) {};
+
+/**
+ * @return {!Array<!Animation>}
+ */
+DocumentTimeline.prototype.getAnimations = function() {};
+
+
+/**
+ * @param {!Array<!AnimationEffect>} children
+ * @param {AnimationEffectTimingProperties=} timing
+ * @constructor
+ * @implements {AnimationEffect}
+ */
+var SequenceEffect = function(children, timing) {};
+
+/** @override */
+SequenceEffect.prototype.getComputedTiming = function() {};
+
+/** @override */
+SequenceEffect.prototype.timing;
+
+/** @type {!Array<!AnimationEffect>} */
+SequenceEffect.prototype.children;
+
+
+/**
+ * @param {!Array<!AnimationEffect>} children
+ * @param {AnimationEffectTimingProperties=} timing
+ * @constructor
+ * @implements {AnimationEffect}
+ */
+var GroupEffect = function(children, timing) {};
+
+/** @override */
+GroupEffect.prototype.getComputedTiming = function() {};
+
+/** @override */
+GroupEffect.prototype.timing;
+
+/** @type {!Array<!AnimationEffect>} */
+GroupEffect.prototype.children;
diff --git a/javascript/externs/web/web_app_manifest.js b/javascript/externs/web/web_app_manifest.js
new file mode 100644
index 000000000000..082c0d4dceaf
--- /dev/null
+++ b/javascript/externs/web/web_app_manifest.js
@@ -0,0 +1,50 @@
+/*
+ * Copyright 2017 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/**
+ * @fileoverview Externs for web app manifest APIs.
+ *
+ * @see https://www.w3.org/TR/appmanifest/
+ * @externs
+ */
+
+/**
+ * @see https://www.w3.org/TR/appmanifest/#beforeinstallpromptevent-interface
+ * @constructor
+ * @extends {Event}
+ */
+function BeforeInstallPromptEvent() {}
+
+/** @type {!Promise<{outcome: !AppBannerPromptOutcome}>} */
+BeforeInstallPromptEvent.prototype.userChoice;
+
+/** @return {!Promise<!PromptResponseObject>} */
+BeforeInstallPromptEvent.prototype.prompt = function() {};
+
+/**
+ * @typedef {string}
+ * @see https://www.w3.org/TR/appmanifest/#appbannerpromptoutcome-enum
+ * Possible values: 'accepted', 'dismissed'
+ */
+var AppBannerPromptOutcome;
+
+/** @typedef {{userChoice: !AppBannerPromptOutcome}} */
+var PromptResponseObject;
+
+/** @type {?function(!BeforeInstallPromptEvent)} */
+Window.prototype.onbeforeinstallprompt;
+
+/** @type {?function(!Event)} */
+Window.prototype.onappinstalled;
diff --git a/javascript/externs/web/webassembly.js b/javascript/externs/web/webassembly.js
new file mode 100644
index 000000000000..3dc81ce345ee
--- /dev/null
+++ b/javascript/externs/web/webassembly.js
@@ -0,0 +1,176 @@
+/*
+ * Copyright 2017 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for WebAssembly JS API
+ *
+ *  @see http://webassembly.org/docs/js/
+ *
+ * @externs
+ * @author loorongjie@gmail.com (Loo Rong Jie)
+ */
+
+ /**
+ * @const
+ */
+var WebAssembly = {};
+
+/**
+ * @constructor
+ * @param {!BufferSource} bytes
+ */
+WebAssembly.Module = function(bytes) {};
+
+/**
+ * @constructor
+ * @param {!WebAssembly.Module} moduleObject
+ * @param {Object=} importObject
+ */
+WebAssembly.Instance = function(moduleObject, importObject) {};
+
+/**
+ * @typedef {{initial:number, maximum:(number|undefined)}}
+ */
+var MemoryDescriptor;
+
+/**
+ * @constructor
+ * @param {MemoryDescriptor} memoryDescriptor
+ */
+WebAssembly.Memory = function(memoryDescriptor) {};
+
+/**
+ * @typedef {{element:string, initial:number, maximum:(number|undefined)}}
+ */
+var TableDescriptor;
+
+/**
+ * @constructor
+ * @param {TableDescriptor} tableDescriptor
+ */
+WebAssembly.Table = function(tableDescriptor) {};
+
+/**
+ * @constructor
+ * @extends {Error}
+ */
+WebAssembly.CompileError = function() {};
+
+/**
+ * @constructor
+ * @extends {Error}
+ */
+WebAssembly.LinkError = function() {};
+
+/**
+ * @constructor
+ * @extends {Error}
+ */
+WebAssembly.RuntimeError = function() {};
+
+// Note: Closure compiler does not support function overloading, omit this overload for now.
+// {function(!WebAssembly.Module, Object=):!Promise<!WebAssembly.Instance>}
+/**
+ * @param {!BufferSource} moduleObject
+ * @param {Object=} importObject
+ * @return {!Promise<{module:!WebAssembly.Module, instance:!WebAssembly.Instance}>}
+ */
+WebAssembly.instantiate = function(moduleObject, importObject) {};
+
+/**
+ * @param {!Promise<!Response>} moduleStream
+ * @param {Object=} importObject
+ * @return {!Promise<{module:!WebAssembly.Module, instance:!WebAssembly.Instance}>}
+ */
+WebAssembly.instantiateStreaming = function(moduleStream, importObject) {};
+
+/**
+ * @param {!BufferSource} bytes
+ * @return {!Promise<!WebAssembly.Module>}
+ */
+WebAssembly.compile = function(bytes) {};
+
+/**
+ * @param {!Promise<!Response>} moduleStream
+ * @return {!Promise<!WebAssembly.Module>}
+ */
+WebAssembly.compileStreaming = function(moduleStream) {};
+
+/**
+ * @param {!BufferSource} bytes
+ * @return {boolean}
+ * @nosideeffects
+ */
+WebAssembly.validate = function(bytes) {};
+
+/**
+ * @param {!WebAssembly.Module} moduleObject
+ * @return {!Array<{name:string, kind:string}>}
+ */
+WebAssembly.Module.exports = function(moduleObject) {};
+
+/**
+ * @param {!WebAssembly.Module} moduleObject
+ * @return {!Array<{module:string, name:string, kind:string}>}
+ */
+WebAssembly.Module.imports = function(moduleObject) {};
+
+/**
+ * @param {!WebAssembly.Module} moduleObject
+ * @param {string} sectionName
+ * @return {!Array<!ArrayBuffer>}
+ */
+WebAssembly.Module.customSections = function(moduleObject, sectionName) {};
+
+WebAssembly.Instance.prototype.exports;
+
+/**
+ * @param {number} delta
+ * @return {number}
+ */
+WebAssembly.Memory.prototype.grow = function(delta) {};
+
+/**
+ * @type {!ArrayBuffer}
+ */
+WebAssembly.Memory.prototype.buffer;
+
+/**
+ * @param {number} delta
+ * @return {number}
+ */
+WebAssembly.Table.prototype.grow = function(delta) {};
+
+/**
+ * @type {number}
+ */
+WebAssembly.Table.prototype.length;
+
+/** @typedef {function(...)} */
+var TableFunction;
+
+/**
+ * @param {number} index
+ * @return {TableFunction}
+ */
+WebAssembly.Table.prototype.get = function(index) {};
+
+/**
+ * @param {number} index
+ * @param {?TableFunction} value
+ * @return {undefined}
+ */
+WebAssembly.Table.prototype.set = function(index, value) {};
diff --git a/javascript/externs/web/webgl2.js b/javascript/externs/web/webgl2.js
new file mode 100644
index 000000000000..f8181fc646ba
--- /dev/null
+++ b/javascript/externs/web/webgl2.js
@@ -0,0 +1,2727 @@
+/*
+ * Copyright 2018 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for WebGL functions as described at
+ * http://www.khronos.org/registry/webgl/specs/latest/
+ *
+ * This file is current up to the WebGL 2.0 spec.
+ *
+ * This relies on webgl.js and html5.js being included for WebGL1, Canvas and
+ * Typed Array support.
+ *
+ * @externs
+ */
+
+
+/**
+ * @constructor
+ * @extends {WebGLRenderingContext}
+ */
+function WebGL2RenderingContext() {}
+
+
+
+/** @const {number} */
+WebGL2RenderingContext.UNPACK_ROW_LENGTH;
+
+/** @const {number} */
+WebGL2RenderingContext.UNPACK_SKIP_ROWS;
+
+/** @const {number} */
+WebGL2RenderingContext.UNPACK_SKIP_PIXELS;
+
+/** @const {number} */
+WebGL2RenderingContext.PACK_ROW_LENGTH;
+
+/** @const {number} */
+WebGL2RenderingContext.PACK_SKIP_ROWS;
+
+/** @const {number} */
+WebGL2RenderingContext.PACK_SKIP_PIXELS;
+
+/** @const {number} */
+WebGL2RenderingContext.COLOR;
+
+/** @const {number} */
+WebGL2RenderingContext.DEPTH;
+
+/** @const {number} */
+WebGL2RenderingContext.STENCIL;
+
+/** @const {number} */
+WebGL2RenderingContext.RED;
+
+/** @const {number} */
+WebGL2RenderingContext.RGB8;
+
+/** @const {number} */
+WebGL2RenderingContext.RGBA8;
+
+/** @const {number} */
+WebGL2RenderingContext.RGB10_A2;
+
+/** @const {number} */
+WebGL2RenderingContext.TEXTURE_BINDING_3D;
+
+/** @const {number} */
+WebGL2RenderingContext.UNPACK_SKIP_IMAGES;
+
+/** @const {number} */
+WebGL2RenderingContext.UNPACK_IMAGE_HEIGHT;
+
+/** @const {number} */
+WebGL2RenderingContext.TEXTURE_3D;
+
+/** @const {number} */
+WebGL2RenderingContext.TEXTURE_WRAP_R;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_3D_TEXTURE_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.UNSIGNED_INT_2_10_10_10_REV;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_ELEMENTS_VERTICES;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_ELEMENTS_INDICES;
+
+/** @const {number} */
+WebGL2RenderingContext.TEXTURE_MIN_LOD;
+
+/** @const {number} */
+WebGL2RenderingContext.TEXTURE_MAX_LOD;
+
+/** @const {number} */
+WebGL2RenderingContext.TEXTURE_BASE_LEVEL;
+
+/** @const {number} */
+WebGL2RenderingContext.TEXTURE_MAX_LEVEL;
+
+/** @const {number} */
+WebGL2RenderingContext.MIN;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX;
+
+/** @const {number} */
+WebGL2RenderingContext.DEPTH_COMPONENT24;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_TEXTURE_LOD_BIAS;
+
+/** @const {number} */
+WebGL2RenderingContext.TEXTURE_COMPARE_MODE;
+
+/** @const {number} */
+WebGL2RenderingContext.TEXTURE_COMPARE_FUNC;
+
+/** @const {number} */
+WebGL2RenderingContext.CURRENT_QUERY;
+
+/** @const {number} */
+WebGL2RenderingContext.QUERY_RESULT;
+
+/** @const {number} */
+WebGL2RenderingContext.QUERY_RESULT_AVAILABLE;
+
+/** @const {number} */
+WebGL2RenderingContext.STREAM_READ;
+
+/** @const {number} */
+WebGL2RenderingContext.STREAM_COPY;
+
+/** @const {number} */
+WebGL2RenderingContext.STATIC_READ;
+
+/** @const {number} */
+WebGL2RenderingContext.STATIC_COPY;
+
+/** @const {number} */
+WebGL2RenderingContext.DYNAMIC_READ;
+
+/** @const {number} */
+WebGL2RenderingContext.DYNAMIC_COPY;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_DRAW_BUFFERS;
+
+/** @const {number} */
+WebGL2RenderingContext.DRAW_BUFFER0;
+
+/** @const {number} */
+WebGL2RenderingContext.DRAW_BUFFER1;
+
+/** @const {number} */
+WebGL2RenderingContext.DRAW_BUFFER2;
+
+/** @const {number} */
+WebGL2RenderingContext.DRAW_BUFFER3;
+
+/** @const {number} */
+WebGL2RenderingContext.DRAW_BUFFER4;
+
+/** @const {number} */
+WebGL2RenderingContext.DRAW_BUFFER5;
+
+/** @const {number} */
+WebGL2RenderingContext.DRAW_BUFFER6;
+
+/** @const {number} */
+WebGL2RenderingContext.DRAW_BUFFER7;
+
+/** @const {number} */
+WebGL2RenderingContext.DRAW_BUFFER8;
+
+/** @const {number} */
+WebGL2RenderingContext.DRAW_BUFFER9;
+
+/** @const {number} */
+WebGL2RenderingContext.DRAW_BUFFER10;
+
+/** @const {number} */
+WebGL2RenderingContext.DRAW_BUFFER11;
+
+/** @const {number} */
+WebGL2RenderingContext.DRAW_BUFFER12;
+
+/** @const {number} */
+WebGL2RenderingContext.DRAW_BUFFER13;
+
+/** @const {number} */
+WebGL2RenderingContext.DRAW_BUFFER14;
+
+/** @const {number} */
+WebGL2RenderingContext.DRAW_BUFFER15;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_FRAGMENT_UNIFORM_COMPONENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_VERTEX_UNIFORM_COMPONENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.SAMPLER_3D;
+
+/** @const {number} */
+WebGL2RenderingContext.SAMPLER_2D_SHADOW;
+
+/** @const {number} */
+WebGL2RenderingContext.FRAGMENT_SHADER_DERIVATIVE_HINT;
+
+/** @const {number} */
+WebGL2RenderingContext.PIXEL_PACK_BUFFER;
+
+/** @const {number} */
+WebGL2RenderingContext.PIXEL_UNPACK_BUFFER;
+
+/** @const {number} */
+WebGL2RenderingContext.PIXEL_PACK_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.PIXEL_UNPACK_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.FLOAT_MAT2x3;
+
+/** @const {number} */
+WebGL2RenderingContext.FLOAT_MAT2x4;
+
+/** @const {number} */
+WebGL2RenderingContext.FLOAT_MAT3x2;
+
+/** @const {number} */
+WebGL2RenderingContext.FLOAT_MAT3x4;
+
+/** @const {number} */
+WebGL2RenderingContext.FLOAT_MAT4x2;
+
+/** @const {number} */
+WebGL2RenderingContext.FLOAT_MAT4x3;
+
+/** @const {number} */
+WebGL2RenderingContext.SRGB;
+
+/** @const {number} */
+WebGL2RenderingContext.SRGB8;
+
+/** @const {number} */
+WebGL2RenderingContext.SRGB8_ALPHA8;
+
+/** @const {number} */
+WebGL2RenderingContext.COMPARE_REF_TO_TEXTURE;
+
+/** @const {number} */
+WebGL2RenderingContext.RGBA32F;
+
+/** @const {number} */
+WebGL2RenderingContext.RGB32F;
+
+/** @const {number} */
+WebGL2RenderingContext.RGBA16F;
+
+/** @const {number} */
+WebGL2RenderingContext.RGB16F;
+
+/** @const {number} */
+WebGL2RenderingContext.VERTEX_ATTRIB_ARRAY_INTEGER;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_ARRAY_TEXTURE_LAYERS;
+
+/** @const {number} */
+WebGL2RenderingContext.MIN_PROGRAM_TEXEL_OFFSET;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_PROGRAM_TEXEL_OFFSET;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_VARYING_COMPONENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.TEXTURE_2D_ARRAY;
+
+/** @const {number} */
+WebGL2RenderingContext.TEXTURE_BINDING_2D_ARRAY;
+
+/** @const {number} */
+WebGL2RenderingContext.R11F_G11F_B10F;
+
+/** @const {number} */
+WebGL2RenderingContext.UNSIGNED_INT_10F_11F_11F_REV;
+
+/** @const {number} */
+WebGL2RenderingContext.RGB9_E5;
+
+/** @const {number} */
+WebGL2RenderingContext.UNSIGNED_INT_5_9_9_9_REV;
+
+/** @const {number} */
+WebGL2RenderingContext.TRANSFORM_FEEDBACK_BUFFER_MODE;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.TRANSFORM_FEEDBACK_VARYINGS;
+
+/** @const {number} */
+WebGL2RenderingContext.TRANSFORM_FEEDBACK_BUFFER_START;
+
+/** @const {number} */
+WebGL2RenderingContext.TRANSFORM_FEEDBACK_BUFFER_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN;
+
+/** @const {number} */
+WebGL2RenderingContext.RASTERIZER_DISCARD;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_TRANSFORM_FEEDBACK_SEPARATE_ATTRIBS;
+
+/** @const {number} */
+WebGL2RenderingContext.INTERLEAVED_ATTRIBS;
+
+/** @const {number} */
+WebGL2RenderingContext.SEPARATE_ATTRIBS;
+
+/** @const {number} */
+WebGL2RenderingContext.TRANSFORM_FEEDBACK_BUFFER;
+
+/** @const {number} */
+WebGL2RenderingContext.TRANSFORM_FEEDBACK_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.RGBA32UI;
+
+/** @const {number} */
+WebGL2RenderingContext.RGB32UI;
+
+/** @const {number} */
+WebGL2RenderingContext.RGBA16UI;
+
+/** @const {number} */
+WebGL2RenderingContext.RGB16UI;
+
+/** @const {number} */
+WebGL2RenderingContext.RGBA8UI;
+
+/** @const {number} */
+WebGL2RenderingContext.RGB8UI;
+
+/** @const {number} */
+WebGL2RenderingContext.RGBA32I;
+
+/** @const {number} */
+WebGL2RenderingContext.RGB32I;
+
+/** @const {number} */
+WebGL2RenderingContext.RGBA16I;
+
+/** @const {number} */
+WebGL2RenderingContext.RGB16I;
+
+/** @const {number} */
+WebGL2RenderingContext.RGBA8I;
+
+/** @const {number} */
+WebGL2RenderingContext.RGB8I;
+
+/** @const {number} */
+WebGL2RenderingContext.RED_INTEGER;
+
+/** @const {number} */
+WebGL2RenderingContext.RGB_INTEGER;
+
+/** @const {number} */
+WebGL2RenderingContext.RGBA_INTEGER;
+
+/** @const {number} */
+WebGL2RenderingContext.SAMPLER_2D_ARRAY;
+
+/** @const {number} */
+WebGL2RenderingContext.SAMPLER_2D_ARRAY_SHADOW;
+
+/** @const {number} */
+WebGL2RenderingContext.SAMPLER_CUBE_SHADOW;
+
+/** @const {number} */
+WebGL2RenderingContext.UNSIGNED_INT_VEC2;
+
+/** @const {number} */
+WebGL2RenderingContext.UNSIGNED_INT_VEC3;
+
+/** @const {number} */
+WebGL2RenderingContext.UNSIGNED_INT_VEC4;
+
+/** @const {number} */
+WebGL2RenderingContext.INT_SAMPLER_2D;
+
+/** @const {number} */
+WebGL2RenderingContext.INT_SAMPLER_3D;
+
+/** @const {number} */
+WebGL2RenderingContext.INT_SAMPLER_CUBE;
+
+/** @const {number} */
+WebGL2RenderingContext.INT_SAMPLER_2D_ARRAY;
+
+/** @const {number} */
+WebGL2RenderingContext.UNSIGNED_INT_SAMPLER_2D;
+
+/** @const {number} */
+WebGL2RenderingContext.UNSIGNED_INT_SAMPLER_3D;
+
+/** @const {number} */
+WebGL2RenderingContext.UNSIGNED_INT_SAMPLER_CUBE;
+
+/** @const {number} */
+WebGL2RenderingContext.UNSIGNED_INT_SAMPLER_2D_ARRAY;
+
+/** @const {number} */
+WebGL2RenderingContext.DEPTH_COMPONENT32F;
+
+/** @const {number} */
+WebGL2RenderingContext.DEPTH32F_STENCIL8;
+
+/** @const {number} */
+WebGL2RenderingContext.FLOAT_32_UNSIGNED_INT_24_8_REV;
+
+/** @const {number} */
+WebGL2RenderingContext.FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING;
+
+/** @const {number} */
+WebGL2RenderingContext.FRAMEBUFFER_ATTACHMENT_COMPONENT_TYPE;
+
+/** @const {number} */
+WebGL2RenderingContext.FRAMEBUFFER_ATTACHMENT_RED_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.FRAMEBUFFER_ATTACHMENT_GREEN_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.FRAMEBUFFER_ATTACHMENT_BLUE_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.FRAMEBUFFER_ATTACHMENT_ALPHA_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.FRAMEBUFFER_ATTACHMENT_DEPTH_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.FRAMEBUFFER_ATTACHMENT_STENCIL_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.FRAMEBUFFER_DEFAULT;
+
+/** @const {number} */
+WebGL2RenderingContext.DEPTH_STENCIL_ATTACHMENT;
+
+/** @const {number} */
+WebGL2RenderingContext.DEPTH_STENCIL;
+
+/** @const {number} */
+WebGL2RenderingContext.UNSIGNED_INT_24_8;
+
+/** @const {number} */
+WebGL2RenderingContext.DEPTH24_STENCIL8;
+
+/** @const {number} */
+WebGL2RenderingContext.UNSIGNED_NORMALIZED;
+
+/** @const {number} */
+WebGL2RenderingContext.DRAW_FRAMEBUFFER_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.READ_FRAMEBUFFER;
+
+/** @const {number} */
+WebGL2RenderingContext.DRAW_FRAMEBUFFER;
+
+/** @const {number} */
+WebGL2RenderingContext.READ_FRAMEBUFFER_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.RENDERBUFFER_SAMPLES;
+
+/** @const {number} */
+WebGL2RenderingContext.FRAMEBUFFER_ATTACHMENT_TEXTURE_LAYER;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_COLOR_ATTACHMENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.COLOR_ATTACHMENT1;
+
+/** @const {number} */
+WebGL2RenderingContext.COLOR_ATTACHMENT2;
+
+/** @const {number} */
+WebGL2RenderingContext.COLOR_ATTACHMENT3;
+
+/** @const {number} */
+WebGL2RenderingContext.COLOR_ATTACHMENT4;
+
+/** @const {number} */
+WebGL2RenderingContext.COLOR_ATTACHMENT5;
+
+/** @const {number} */
+WebGL2RenderingContext.COLOR_ATTACHMENT6;
+
+/** @const {number} */
+WebGL2RenderingContext.COLOR_ATTACHMENT7;
+
+/** @const {number} */
+WebGL2RenderingContext.COLOR_ATTACHMENT8;
+
+/** @const {number} */
+WebGL2RenderingContext.COLOR_ATTACHMENT9;
+
+/** @const {number} */
+WebGL2RenderingContext.COLOR_ATTACHMENT10;
+
+/** @const {number} */
+WebGL2RenderingContext.COLOR_ATTACHMENT11;
+
+/** @const {number} */
+WebGL2RenderingContext.COLOR_ATTACHMENT12;
+
+/** @const {number} */
+WebGL2RenderingContext.COLOR_ATTACHMENT13;
+
+/** @const {number} */
+WebGL2RenderingContext.COLOR_ATTACHMENT14;
+
+/** @const {number} */
+WebGL2RenderingContext.COLOR_ATTACHMENT15;
+
+/** @const {number} */
+WebGL2RenderingContext.FRAMEBUFFER_INCOMPLETE_MULTISAMPLE;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_SAMPLES;
+
+/** @const {number} */
+WebGL2RenderingContext.HALF_FLOAT;
+
+/** @const {number} */
+WebGL2RenderingContext.RG;
+
+/** @const {number} */
+WebGL2RenderingContext.RG_INTEGER;
+
+/** @const {number} */
+WebGL2RenderingContext.R8;
+
+/** @const {number} */
+WebGL2RenderingContext.RG8;
+
+/** @const {number} */
+WebGL2RenderingContext.R16F;
+
+/** @const {number} */
+WebGL2RenderingContext.R32F;
+
+/** @const {number} */
+WebGL2RenderingContext.RG16F;
+
+/** @const {number} */
+WebGL2RenderingContext.RG32F;
+
+/** @const {number} */
+WebGL2RenderingContext.R8I;
+
+/** @const {number} */
+WebGL2RenderingContext.R8UI;
+
+/** @const {number} */
+WebGL2RenderingContext.R16I;
+
+/** @const {number} */
+WebGL2RenderingContext.R16UI;
+
+/** @const {number} */
+WebGL2RenderingContext.R32I;
+
+/** @const {number} */
+WebGL2RenderingContext.R32UI;
+
+/** @const {number} */
+WebGL2RenderingContext.RG8I;
+
+/** @const {number} */
+WebGL2RenderingContext.RG8UI;
+
+/** @const {number} */
+WebGL2RenderingContext.RG16I;
+
+/** @const {number} */
+WebGL2RenderingContext.RG16UI;
+
+/** @const {number} */
+WebGL2RenderingContext.RG32I;
+
+/** @const {number} */
+WebGL2RenderingContext.RG32UI;
+
+/** @const {number} */
+WebGL2RenderingContext.VERTEX_ARRAY_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.R8_SNORM;
+
+/** @const {number} */
+WebGL2RenderingContext.RG8_SNORM;
+
+/** @const {number} */
+WebGL2RenderingContext.RGB8_SNORM;
+
+/** @const {number} */
+WebGL2RenderingContext.RGBA8_SNORM;
+
+/** @const {number} */
+WebGL2RenderingContext.SIGNED_NORMALIZED;
+
+/** @const {number} */
+WebGL2RenderingContext.COPY_READ_BUFFER;
+
+/** @const {number} */
+WebGL2RenderingContext.COPY_WRITE_BUFFER;
+
+/** @const {number} */
+WebGL2RenderingContext.COPY_READ_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.COPY_WRITE_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.UNIFORM_BUFFER;
+
+/** @const {number} */
+WebGL2RenderingContext.UNIFORM_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.UNIFORM_BUFFER_START;
+
+/** @const {number} */
+WebGL2RenderingContext.UNIFORM_BUFFER_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_VERTEX_UNIFORM_BLOCKS;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_FRAGMENT_UNIFORM_BLOCKS;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_COMBINED_UNIFORM_BLOCKS;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_UNIFORM_BUFFER_BINDINGS;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_UNIFORM_BLOCK_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_COMBINED_VERTEX_UNIFORM_COMPONENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_COMBINED_FRAGMENT_UNIFORM_COMPONENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.UNIFORM_BUFFER_OFFSET_ALIGNMENT;
+
+/** @const {number} */
+WebGL2RenderingContext.ACTIVE_UNIFORM_BLOCKS;
+
+/** @const {number} */
+WebGL2RenderingContext.UNIFORM_TYPE;
+
+/** @const {number} */
+WebGL2RenderingContext.UNIFORM_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.UNIFORM_BLOCK_INDEX;
+
+/** @const {number} */
+WebGL2RenderingContext.UNIFORM_OFFSET;
+
+/** @const {number} */
+WebGL2RenderingContext.UNIFORM_ARRAY_STRIDE;
+
+/** @const {number} */
+WebGL2RenderingContext.UNIFORM_MATRIX_STRIDE;
+
+/** @const {number} */
+WebGL2RenderingContext.UNIFORM_IS_ROW_MAJOR;
+
+/** @const {number} */
+WebGL2RenderingContext.UNIFORM_BLOCK_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.UNIFORM_BLOCK_DATA_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.UNIFORM_BLOCK_ACTIVE_UNIFORMS;
+
+/** @const {number} */
+WebGL2RenderingContext.UNIFORM_BLOCK_ACTIVE_UNIFORM_INDICES;
+
+/** @const {number} */
+WebGL2RenderingContext.UNIFORM_BLOCK_REFERENCED_BY_VERTEX_SHADER;
+
+/** @const {number} */
+WebGL2RenderingContext.UNIFORM_BLOCK_REFERENCED_BY_FRAGMENT_SHADER;
+
+/** @const {number} */
+WebGL2RenderingContext.INVALID_INDEX;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_VERTEX_OUTPUT_COMPONENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_FRAGMENT_INPUT_COMPONENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_SERVER_WAIT_TIMEOUT;
+
+/** @const {number} */
+WebGL2RenderingContext.OBJECT_TYPE;
+
+/** @const {number} */
+WebGL2RenderingContext.SYNC_CONDITION;
+
+/** @const {number} */
+WebGL2RenderingContext.SYNC_STATUS;
+
+/** @const {number} */
+WebGL2RenderingContext.SYNC_FLAGS;
+
+/** @const {number} */
+WebGL2RenderingContext.SYNC_FENCE;
+
+/** @const {number} */
+WebGL2RenderingContext.SYNC_GPU_COMMANDS_COMPLETE;
+
+/** @const {number} */
+WebGL2RenderingContext.UNSIGNALED;
+
+/** @const {number} */
+WebGL2RenderingContext.SIGNALED;
+
+/** @const {number} */
+WebGL2RenderingContext.ALREADY_SIGNALED;
+
+/** @const {number} */
+WebGL2RenderingContext.TIMEOUT_EXPIRED;
+
+/** @const {number} */
+WebGL2RenderingContext.CONDITION_SATISFIED;
+
+/** @const {number} */
+WebGL2RenderingContext.WAIT_FAILED;
+
+/** @const {number} */
+WebGL2RenderingContext.SYNC_FLUSH_COMMANDS_BIT;
+
+/** @const {number} */
+WebGL2RenderingContext.VERTEX_ATTRIB_ARRAY_DIVISOR;
+
+/** @const {number} */
+WebGL2RenderingContext.ANY_SAMPLES_PASSED;
+
+/** @const {number} */
+WebGL2RenderingContext.ANY_SAMPLES_PASSED_CONSERVATIVE;
+
+/** @const {number} */
+WebGL2RenderingContext.SAMPLER_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.RGB10_A2UI;
+
+/** @const {number} */
+WebGL2RenderingContext.INT_2_10_10_10_REV;
+
+/** @const {number} */
+WebGL2RenderingContext.TRANSFORM_FEEDBACK;
+
+/** @const {number} */
+WebGL2RenderingContext.TRANSFORM_FEEDBACK_PAUSED;
+
+/** @const {number} */
+WebGL2RenderingContext.TRANSFORM_FEEDBACK_ACTIVE;
+
+/** @const {number} */
+WebGL2RenderingContext.TRANSFORM_FEEDBACK_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.TEXTURE_IMMUTABLE_FORMAT;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_ELEMENT_INDEX;
+
+/** @const {number} */
+WebGL2RenderingContext.TEXTURE_IMMUTABLE_LEVELS;
+
+/** @const {number} */
+WebGL2RenderingContext.TIMEOUT_IGNORED;
+
+/** @const {number} */
+WebGL2RenderingContext.MAX_CLIENT_WAIT_TIMEOUT_WEBGL;
+
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNPACK_ROW_LENGTH;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNPACK_SKIP_ROWS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNPACK_SKIP_PIXELS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.PACK_ROW_LENGTH;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.PACK_SKIP_ROWS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.PACK_SKIP_PIXELS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COLOR;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DEPTH;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.STENCIL;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RED;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGB8;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGBA8;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGB10_A2;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TEXTURE_BINDING_3D;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNPACK_SKIP_IMAGES;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNPACK_IMAGE_HEIGHT;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TEXTURE_3D;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TEXTURE_WRAP_R;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_3D_TEXTURE_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNSIGNED_INT_2_10_10_10_REV;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_ELEMENTS_VERTICES;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_ELEMENTS_INDICES;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TEXTURE_MIN_LOD;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TEXTURE_MAX_LOD;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TEXTURE_BASE_LEVEL;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TEXTURE_MAX_LEVEL;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MIN;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DEPTH_COMPONENT24;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_TEXTURE_LOD_BIAS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TEXTURE_COMPARE_MODE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TEXTURE_COMPARE_FUNC;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.CURRENT_QUERY;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.QUERY_RESULT;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.QUERY_RESULT_AVAILABLE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.STREAM_READ;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.STREAM_COPY;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.STATIC_READ;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.STATIC_COPY;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DYNAMIC_READ;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DYNAMIC_COPY;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_DRAW_BUFFERS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DRAW_BUFFER0;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DRAW_BUFFER1;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DRAW_BUFFER2;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DRAW_BUFFER3;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DRAW_BUFFER4;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DRAW_BUFFER5;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DRAW_BUFFER6;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DRAW_BUFFER7;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DRAW_BUFFER8;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DRAW_BUFFER9;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DRAW_BUFFER10;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DRAW_BUFFER11;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DRAW_BUFFER12;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DRAW_BUFFER13;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DRAW_BUFFER14;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DRAW_BUFFER15;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_FRAGMENT_UNIFORM_COMPONENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_VERTEX_UNIFORM_COMPONENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.SAMPLER_3D;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.SAMPLER_2D_SHADOW;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FRAGMENT_SHADER_DERIVATIVE_HINT;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.PIXEL_PACK_BUFFER;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.PIXEL_UNPACK_BUFFER;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.PIXEL_PACK_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.PIXEL_UNPACK_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FLOAT_MAT2x3;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FLOAT_MAT2x4;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FLOAT_MAT3x2;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FLOAT_MAT3x4;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FLOAT_MAT4x2;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FLOAT_MAT4x3;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.SRGB;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.SRGB8;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.SRGB8_ALPHA8;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COMPARE_REF_TO_TEXTURE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGBA32F;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGB32F;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGBA16F;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGB16F;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.VERTEX_ATTRIB_ARRAY_INTEGER;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_ARRAY_TEXTURE_LAYERS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MIN_PROGRAM_TEXEL_OFFSET;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_PROGRAM_TEXEL_OFFSET;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_VARYING_COMPONENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TEXTURE_2D_ARRAY;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TEXTURE_BINDING_2D_ARRAY;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.R11F_G11F_B10F;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNSIGNED_INT_10F_11F_11F_REV;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGB9_E5;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNSIGNED_INT_5_9_9_9_REV;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TRANSFORM_FEEDBACK_BUFFER_MODE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TRANSFORM_FEEDBACK_VARYINGS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TRANSFORM_FEEDBACK_BUFFER_START;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TRANSFORM_FEEDBACK_BUFFER_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RASTERIZER_DISCARD;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS =
+    0x8C8A;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_TRANSFORM_FEEDBACK_SEPARATE_ATTRIBS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.INTERLEAVED_ATTRIBS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.SEPARATE_ATTRIBS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TRANSFORM_FEEDBACK_BUFFER;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TRANSFORM_FEEDBACK_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGBA32UI;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGB32UI;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGBA16UI;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGB16UI;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGBA8UI;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGB8UI;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGBA32I;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGB32I;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGBA16I;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGB16I;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGBA8I;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGB8I;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RED_INTEGER;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGB_INTEGER;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGBA_INTEGER;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.SAMPLER_2D_ARRAY;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.SAMPLER_2D_ARRAY_SHADOW;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.SAMPLER_CUBE_SHADOW;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNSIGNED_INT_VEC2;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNSIGNED_INT_VEC3;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNSIGNED_INT_VEC4;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.INT_SAMPLER_2D;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.INT_SAMPLER_3D;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.INT_SAMPLER_CUBE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.INT_SAMPLER_2D_ARRAY;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNSIGNED_INT_SAMPLER_2D;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNSIGNED_INT_SAMPLER_3D;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNSIGNED_INT_SAMPLER_CUBE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNSIGNED_INT_SAMPLER_2D_ARRAY;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DEPTH_COMPONENT32F;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DEPTH32F_STENCIL8;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FLOAT_32_UNSIGNED_INT_24_8_REV;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FRAMEBUFFER_ATTACHMENT_COMPONENT_TYPE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FRAMEBUFFER_ATTACHMENT_RED_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FRAMEBUFFER_ATTACHMENT_GREEN_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FRAMEBUFFER_ATTACHMENT_BLUE_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FRAMEBUFFER_ATTACHMENT_ALPHA_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FRAMEBUFFER_ATTACHMENT_DEPTH_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FRAMEBUFFER_ATTACHMENT_STENCIL_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FRAMEBUFFER_DEFAULT;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DEPTH_STENCIL_ATTACHMENT;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DEPTH_STENCIL;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNSIGNED_INT_24_8;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DEPTH24_STENCIL8;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNSIGNED_NORMALIZED;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DRAW_FRAMEBUFFER_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.READ_FRAMEBUFFER;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.DRAW_FRAMEBUFFER;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.READ_FRAMEBUFFER_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RENDERBUFFER_SAMPLES;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FRAMEBUFFER_ATTACHMENT_TEXTURE_LAYER;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_COLOR_ATTACHMENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COLOR_ATTACHMENT1;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COLOR_ATTACHMENT2;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COLOR_ATTACHMENT3;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COLOR_ATTACHMENT4;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COLOR_ATTACHMENT5;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COLOR_ATTACHMENT6;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COLOR_ATTACHMENT7;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COLOR_ATTACHMENT8;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COLOR_ATTACHMENT9;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COLOR_ATTACHMENT10;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COLOR_ATTACHMENT11;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COLOR_ATTACHMENT12;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COLOR_ATTACHMENT13;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COLOR_ATTACHMENT14;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COLOR_ATTACHMENT15;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.FRAMEBUFFER_INCOMPLETE_MULTISAMPLE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_SAMPLES;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.HALF_FLOAT;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RG;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RG_INTEGER;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.R8;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RG8;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.R16F;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.R32F;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RG16F;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RG32F;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.R8I;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.R8UI;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.R16I;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.R16UI;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.R32I;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.R32UI;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RG8I;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RG8UI;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RG16I;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RG16UI;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RG32I;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RG32UI;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.VERTEX_ARRAY_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.R8_SNORM;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RG8_SNORM;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGB8_SNORM;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGBA8_SNORM;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.SIGNED_NORMALIZED;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COPY_READ_BUFFER;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COPY_WRITE_BUFFER;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COPY_READ_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.COPY_WRITE_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNIFORM_BUFFER;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNIFORM_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNIFORM_BUFFER_START;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNIFORM_BUFFER_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_VERTEX_UNIFORM_BLOCKS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_FRAGMENT_UNIFORM_BLOCKS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_COMBINED_UNIFORM_BLOCKS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_UNIFORM_BUFFER_BINDINGS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_UNIFORM_BLOCK_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_COMBINED_VERTEX_UNIFORM_COMPONENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_COMBINED_FRAGMENT_UNIFORM_COMPONENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNIFORM_BUFFER_OFFSET_ALIGNMENT;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.ACTIVE_UNIFORM_BLOCKS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNIFORM_TYPE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNIFORM_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNIFORM_BLOCK_INDEX;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNIFORM_OFFSET;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNIFORM_ARRAY_STRIDE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNIFORM_MATRIX_STRIDE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNIFORM_IS_ROW_MAJOR;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNIFORM_BLOCK_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNIFORM_BLOCK_DATA_SIZE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNIFORM_BLOCK_ACTIVE_UNIFORMS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNIFORM_BLOCK_ACTIVE_UNIFORM_INDICES;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNIFORM_BLOCK_REFERENCED_BY_VERTEX_SHADER;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNIFORM_BLOCK_REFERENCED_BY_FRAGMENT_SHADER;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.INVALID_INDEX;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_VERTEX_OUTPUT_COMPONENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_FRAGMENT_INPUT_COMPONENTS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_SERVER_WAIT_TIMEOUT;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.OBJECT_TYPE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.SYNC_CONDITION;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.SYNC_STATUS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.SYNC_FLAGS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.SYNC_FENCE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.SYNC_GPU_COMMANDS_COMPLETE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.UNSIGNALED;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.SIGNALED;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.ALREADY_SIGNALED;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TIMEOUT_EXPIRED;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.CONDITION_SATISFIED;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.WAIT_FAILED;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.SYNC_FLUSH_COMMANDS_BIT;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.VERTEX_ATTRIB_ARRAY_DIVISOR;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.ANY_SAMPLES_PASSED;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.ANY_SAMPLES_PASSED_CONSERVATIVE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.SAMPLER_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.RGB10_A2UI;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.INT_2_10_10_10_REV;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TRANSFORM_FEEDBACK;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TRANSFORM_FEEDBACK_PAUSED;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TRANSFORM_FEEDBACK_ACTIVE;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TRANSFORM_FEEDBACK_BINDING;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TEXTURE_IMMUTABLE_FORMAT;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_ELEMENT_INDEX;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TEXTURE_IMMUTABLE_LEVELS;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.TIMEOUT_IGNORED;
+
+/** @const {number} */
+WebGL2RenderingContext.prototype.MAX_CLIENT_WAIT_TIMEOUT_WEBGL;
+
+/* Buffer objects */
+
+/**
+ * @param {number} target
+ * @param {?ArrayBufferView|?ArrayBuffer|number} data
+ * @param {number} usage
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_length
+ * @return {undefined}
+ * @override
+ */
+WebGL2RenderingContext.prototype.bufferData = function(
+    target, data, usage, opt_srcOffset, opt_length) {};
+
+/**
+ * @param {number} target
+ * @param {number} offset
+ * @param {?ArrayBufferView|?ArrayBuffer} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_length
+ * @return {undefined}
+ * @override
+ */
+WebGL2RenderingContext.prototype.bufferSubData = function(
+    target, offset, data, opt_srcOffset, opt_length) {};
+
+/**
+ * @param {number} readTarget
+ * @param {number} writeTarget
+ * @param {number} readOffset
+ * @param {number} writeOffset
+ * @param {number} size
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.copyBufferSubData = function(
+    readTarget, writeTarget, readOffset, writeOffset, size) {};
+
+/**
+ * @param {number} target
+ * @param {number} srcByteOffset
+ * @param {?ArrayBufferView|?ArrayBuffer} dstBuffer
+ * @param {number=} opt_dstOffset
+ * @param {number=} opt_length
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.getBufferSubData = function(
+    target, srcByteOffset, dstBuffer, opt_dstOffset, opt_length) {};
+
+/* Framebuffer objects */
+
+/**
+ * @param {number} srcX0
+ * @param {number} srcY0
+ * @param {number} srcX1
+ * @param {number} srcY1
+ * @param {number} dstX0
+ * @param {number} dstY0
+ * @param {number} dstX1
+ * @param {number} dstY1
+ * @param {number} mask
+ * @param {number} filter
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.blitFramebuffer = function(
+    srcX0, srcY0, srcX1, srcY1, dstX0, dstY0, dstX1, dstY1, mask, filter) {};
+
+/**
+ * @param {number} target
+ * @param {number} attachment
+ * @param {?WebGLTexture} texture
+ * @param {number} level
+ * @param {number} layer
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.framebufferTextureLayer = function(
+    target, attachment, texture, level, layer) {};
+
+/**
+ * @param {number} target
+ * @param {!Array<number>} attachments
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.invalidateFramebuffer = function(
+    target, attachments) {};
+
+/**
+ * @param {number} target
+ * @param {!Array<number>} attachments
+ * @param {number} x
+ * @param {number} y
+ * @param {number} width
+ * @param {number} height
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.invalidateSubFramebuffer = function(
+    target, attachments, x, y, width, height) {};
+
+/**
+ * @param {number} src
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.readBuffer = function(src) {};
+
+/* Renderbuffer objects */
+
+/**
+ * @param {number} target
+ * @param {number} internalformat
+ * @param {number} pname
+ * @return {*}
+ * @nosideeffects
+ */
+WebGL2RenderingContext.prototype.getInternalformatParameter = function(
+    target, internalformat, pname) {};
+
+/**
+ * @param {number} target
+ * @param {number} samples
+ * @param {number} internalformat
+ * @param {number} width
+ * @param {number} height
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.renderbufferStorageMultisample = function(
+    target, samples, internalformat, width, height) {};
+
+/* Texture objects */
+
+/**
+ * @param {number} target
+ * @param {number} levels
+ * @param {number} internalformat
+ * @param {number} width
+ * @param {number} height
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.texStorage2D = function(
+    target, levels, internalformat, width, height) {};
+
+/**
+ * @param {number} target
+ * @param {number} levels
+ * @param {number} internalformat
+ * @param {number} width
+ * @param {number} height
+ * @param {number} depth
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.texStorage3D = function(
+    target, levels, internalformat, width, height, depth) {};
+
+/**
+ * @param {number} target
+ * @param {number} level
+ * @param {number} internalformat
+ * @param {number} formatOrWidth
+ * @param {number} typeOrHeight
+ * @param {?TexImageSource|number} imgOrBorder
+ * @param {number=} opt_format
+ * @param {number=} opt_type
+ * @param {?ArrayBufferView|?TexImageSource|number=} opt_imgOrOffset
+ * @param {number=} opt_srcOffset
+ * @return {undefined}
+ * @override
+ */
+WebGL2RenderingContext.prototype.texImage2D = function(
+    target, level, internalformat, formatOrWidth, typeOrHeight, imgOrBorder,
+    opt_format, opt_type, opt_imgOrOffset, opt_srcOffset) {};
+
+/**
+ * @param {number} target
+ * @param {number} level
+ * @param {number} xoffset
+ * @param {number} yoffset
+ * @param {number} formatOrWidth
+ * @param {number} typeOrHeight
+ * @param {?TexImageSource|number} dataOrFormat
+ * @param {number=} opt_type
+ * @param {?ArrayBufferView|?TexImageSource|number=} opt_imgOrOffset
+ * @param {number=} opt_srcOffset
+ * @return {undefined}
+ * @override
+ */
+WebGL2RenderingContext.prototype.texSubImage2D = function(
+    target, level, xoffset, yoffset, formatOrWidth, typeOrHeight, dataOrFormat,
+    opt_type, opt_imgOrOffset, opt_srcOffset) {};
+
+/**
+ * @param {number} target
+ * @param {number} level
+ * @param {number} internalformat
+ * @param {number} width
+ * @param {number} height
+ * @param {number} depth
+ * @param {number} border
+ * @param {number} format
+ * @param {number} type
+ * @param {?ArrayBufferView|?TexImageSource|number} srcData
+ * @param {number=} opt_srcOffset
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.texImage3D = function(
+    target, level, internalformat, width, height, depth, border, format, type,
+    srcData, opt_srcOffset) {};
+
+/**
+ * @param {number} target
+ * @param {number} level
+ * @param {number} xoffset
+ * @param {number} yoffset
+ * @param {number} zoffset
+ * @param {number} width
+ * @param {number} height
+ * @param {number} depth
+ * @param {number} format
+ * @param {number} type
+ * @param {?ArrayBufferView|?TexImageSource|number} srcData
+ * @param {number=} opt_srcOffset
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.texSubImage3D = function(
+    target, level, xoffset, yoffset, zoffset, width, height, depth, format,
+    type, srcData, opt_srcOffset) {};
+
+/**
+ * @param {number} target
+ * @param {number} level
+ * @param {number} xoffset
+ * @param {number} yoffset
+ * @param {number} zoffset
+ * @param {number} x
+ * @param {number} y
+ * @param {number} width
+ * @param {number} height
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.copyTexSubImage3D = function(
+    target, level, xoffset, yoffset, zoffset, x, y, width, height) {};
+
+/**
+ * @param {number} target
+ * @param {number} level
+ * @param {number} internalformat
+ * @param {number} width
+ * @param {number} height
+ * @param {number} border
+ * @param {?ArrayBufferView|number} srcDataOrSize
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLengthOverride
+ * @return {undefined}
+ * @override
+ */
+WebGL2RenderingContext.prototype.compressedTexImage2D = function(
+    target, level, internalformat, width, height, border, srcDataOrSize,
+    opt_srcOffset, opt_srcLengthOverride) {};
+
+/**
+ * @param {number} target
+ * @param {number} level
+ * @param {number} internalformat
+ * @param {number} width
+ * @param {number} height
+ * @param {number} depth
+ * @param {number} border
+ * @param {!ArrayBufferView|number} srcDataOrSize
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLengthOverride
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.compressedTexImage3D = function(
+    target, level, internalformat, width, height, depth, border, srcDataOrSize,
+    opt_srcOffset, opt_srcLengthOverride) {};
+
+
+/**
+ * @param {number} target
+ * @param {number} level
+ * @param {number} xoffset
+ * @param {number} yoffset
+ * @param {number} width
+ * @param {number} height
+ * @param {number} format
+ * @param {?ArrayBufferView|number} srcDataOrSize
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLengthOverride
+ * @return {undefined}
+ * @override
+ */
+WebGL2RenderingContext.prototype.compressedTexSubImage2D = function(
+    target, level, xoffset, yoffset, width, height, format, srcDataOrSize,
+    opt_srcOffset, opt_srcLengthOverride) {};
+
+
+/**
+ * @param {number} target
+ * @param {number} level
+ * @param {number} xoffset
+ * @param {number} yoffset
+ * @param {number} zoffset
+ * @param {number} width
+ * @param {number} height
+ * @param {number} depth
+ * @param {number} format
+ * @param {!ArrayBufferView|number} srcDataOrSize
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLengthOverride
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.compressedTexSubImage3D = function(
+    target, level, xoffset, yoffset, zoffset, width, height, depth, format,
+    srcDataOrSize, opt_srcOffset, opt_srcLengthOverride) {};
+
+/* Programs and shaders */
+
+/**
+ * @param {!WebGLProgram} program
+ * @param {string} name
+ * @return {number}
+ * @nosideeffects
+ */
+WebGL2RenderingContext.prototype.getFragDataLocation = function(
+    program, name) {};
+
+/* Uniforms */
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {number} v0
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.uniform1ui = function(location, v0) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {number} v0
+ * @param {number} v1
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.uniform2ui = function(location, v0, v1) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {number} v0
+ * @param {number} v1
+ * @param {number} v2
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.uniform3ui = function(location, v0, v1, v2) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {number} v0
+ * @param {number} v1
+ * @param {number} v2
+ * @param {number} v3
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.uniform4ui = function(
+    location, v0, v1, v2, v3) {};
+
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {?Float32Array|?Array<number>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ * @override
+ */
+WebGL2RenderingContext.prototype.uniform1fv = function(
+    location, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {?Float32Array|?Array<number>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ * @override
+ */
+WebGL2RenderingContext.prototype.uniform2fv = function(
+    location, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {?Float32Array|?Array<number>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ * @override
+ */
+WebGL2RenderingContext.prototype.uniform3fv = function(
+    location, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {?Float32Array|?Array<number>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ * @override
+ */
+WebGL2RenderingContext.prototype.uniform4fv = function(
+    location, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {?Int32Array|?Array<number>|?Array<boolean>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ * @override
+ */
+WebGL2RenderingContext.prototype.uniform1iv = function(
+    location, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {?Int32Array|?Array<number>|?Array<boolean>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ * @override
+ */
+WebGL2RenderingContext.prototype.uniform2iv = function(
+    location, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {?Int32Array|?Array<number>|?Array<boolean>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ * @override
+ */
+WebGL2RenderingContext.prototype.uniform3iv = function(
+    location, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {?Int32Array|?Array<number>|?Array<boolean>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ * @override
+ */
+WebGL2RenderingContext.prototype.uniform4iv = function(
+    location, data, opt_srcOffset, opt_srcLength) {};
+
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {!Uint32Array|!Array<number>|!Array<boolean>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.uniform1uiv = function(
+    location, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {!Uint32Array|!Array<number>|!Array<boolean>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.uniform2uiv = function(
+    location, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {!Uint32Array|!Array<number>|!Array<boolean>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.uniform3uiv = function(
+    location, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {!Uint32Array|!Array<number>|!Array<boolean>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.uniform4uiv = function(
+    location, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {boolean} transpose
+ * @param {?Float32Array|?Array<number>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ * @override
+ */
+WebGL2RenderingContext.prototype.uniformMatrix2fv = function(
+    location, transpose, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {boolean} transpose
+ * @param {!Float32Array|!Array<number>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.uniformMatrix3x2fv = function(
+    location, transpose, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {boolean} transpose
+ * @param {!Float32Array|!Array<number>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.uniformMatrix4x2fv = function(
+    location, transpose, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {boolean} transpose
+ * @param {!Float32Array|!Array<number>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.uniformMatrix2x3fv = function(
+    location, transpose, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {boolean} transpose
+ * @param {?Float32Array|?Array<number>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ * @override
+ */
+WebGL2RenderingContext.prototype.uniformMatrix3fv = function(
+    location, transpose, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {boolean} transpose
+ * @param {!Float32Array|!Array<number>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.uniformMatrix4x3fv = function(
+    location, transpose, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {boolean} transpose
+ * @param {!Float32Array|!Array<number>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.uniformMatrix2x4fv = function(
+    location, transpose, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {boolean} transpose
+ * @param {!Float32Array|!Array<number>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.uniformMatrix3x4fv = function(
+    location, transpose, data, opt_srcOffset, opt_srcLength) {};
+
+/**
+ * @param {?WebGLUniformLocation} location
+ * @param {boolean} transpose
+ * @param {?Float32Array|?Array<number>} data
+ * @param {number=} opt_srcOffset
+ * @param {number=} opt_srcLength
+ * @return {undefined}
+ * @override
+ */
+WebGL2RenderingContext.prototype.uniformMatrix4fv = function(
+    location, transpose, data, opt_srcOffset, opt_srcLength) {};
+
+/* Vertex attribs */
+
+/**
+ * @param {number} index
+ * @param {number} x
+ * @param {number} y
+ * @param {number} z
+ * @param {number} w
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.vertexAttribI4i = function(
+    index, x, y, z, w) {};
+
+/**
+ * @param {number} index
+ * @param {!Int32Array|!Array<number>|!Array<boolean>} values
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.vertexAttribI4iv = function(index, values) {};
+
+/**
+ * @param {number} index
+ * @param {number} x
+ * @param {number} y
+ * @param {number} z
+ * @param {number} w
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.vertexAttribI4ui = function(
+    index, x, y, z, w) {};
+
+/**
+ * @param {number} index
+ * @param {!Uint32Array|!Array<number>|!Array<boolean>} values
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.vertexAttribI4uiv = function(index, values) {};
+
+/**
+ * @param {number} index
+ * @param {number} size
+ * @param {number} type
+ * @param {number} stride
+ * @param {number} offset
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.vertexAttribIPointer = function(
+    index, size, type, stride, offset) {};
+
+/* Writing to the drawing buffer */
+
+/**
+ * @param {number} index
+ * @param {number} divisor
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.vertexAttribDivisor = function(
+    index, divisor) {};
+
+/**
+ * @param {number} mode
+ * @param {number} first
+ * @param {number} count
+ * @param {number} instanceCount
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.drawArraysInstanced = function(
+    mode, first, count, instanceCount) {};
+
+/**
+ * @param {number} mode
+ * @param {number} count
+ * @param {number} type
+ * @param {number} offset
+ * @param {number} instanceCount
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.drawElementsInstanced = function(
+    mode, count, type, offset, instanceCount) {};
+
+/**
+ * @param {number} mode
+ * @param {number} start
+ * @param {number} end
+ * @param {number} count
+ * @param {number} type
+ * @param {number} offset
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.drawRangeElements = function(
+    mode, start, end, count, type, offset) {};
+
+/* Reading back pixels */
+
+/**
+ * @param {number} x
+ * @param {number} y
+ * @param {number} width
+ * @param {number} height
+ * @param {number} format
+ * @param {number} type
+ * @param {?ArrayBufferView|number} dstDataOrOffset
+ * @param {number=} opt_dstOffset
+ * @return {undefined}
+ * @override
+ */
+WebGL2RenderingContext.prototype.readPixels = function(
+    x, y, width, height, format, type, dstDataOrOffset, opt_dstOffset) {};
+
+/* Multiple Render Targets */
+
+/**
+ * @param {!Array<number>} buffers
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.drawBuffers = function(buffers) {};
+
+
+/**
+ * @param {number} buffer
+ * @param {number} drawbuffer
+ * @param {!Float32Array|!Array<number>} values
+ * @param {number=} opt_srcOffset
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.clearBufferfv = function(
+    buffer, drawbuffer, values, opt_srcOffset) {};
+
+/**
+ * @param {number} buffer
+ * @param {number} drawbuffer
+ * @param {!Int32Array|!Array<number>|!Array<boolean>} values
+ * @param {number=} opt_srcOffset
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.clearBufferiv = function(
+    buffer, drawbuffer, values, opt_srcOffset) {};
+
+/**
+ * @param {number} buffer
+ * @param {number} drawbuffer
+ * @param {!Uint32Array|!Array<number>|!Array<boolean>} values
+ * @param {number=} opt_srcOffset
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.clearBufferuiv = function(
+    buffer, drawbuffer, values, opt_srcOffset) {};
+
+/**
+ * @param {number} buffer
+ * @param {number} drawbuffer
+ * @param {number} depth
+ * @param {number} stencil
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.clearBufferfi = function(
+    buffer, drawbuffer, depth, stencil) {};
+
+/* Query Objects */
+
+/**
+ * @return {?WebGLQuery}
+ */
+WebGL2RenderingContext.prototype.createQuery = function() {};
+
+/**
+ * @param {?WebGLQuery} query
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.deleteQuery = function(query) {};
+
+/**
+ * @param {?WebGLQuery} query
+ * @return {boolean}
+ */
+WebGL2RenderingContext.prototype.isQuery = function(query) {};
+
+/**
+ * @param {number} target
+ * @param {!WebGLQuery} query
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.beginQuery = function(target, query) {};
+
+/**
+ * @param {number} target
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.endQuery = function(target) {};
+
+/**
+ * @param {number} target
+ * @param {number} pname
+ * @return {?WebGLQuery}
+ * @nosideeffects
+ */
+WebGL2RenderingContext.prototype.getQuery = function(target, pname) {};
+
+/**
+ * @param {!WebGLQuery} query
+ * @param {number} pname
+ * @return {*}
+ */
+WebGL2RenderingContext.prototype.getQueryParameter = function(query, pname) {};
+
+/* Sampler Objects */
+
+/**
+ * @return {?WebGLSampler}
+ */
+WebGL2RenderingContext.prototype.createSampler = function() {};
+
+/**
+ * @param {?WebGLSampler} sampler
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.deleteSampler = function(sampler) {};
+
+/**
+ * @param {?WebGLSampler} sampler
+ * @return {boolean}
+ */
+WebGL2RenderingContext.prototype.isSampler = function(sampler) {};
+
+/**
+ * @param {number} unit
+ * @param {?WebGLSampler} sampler
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.bindSampler = function(unit, sampler) {};
+
+/**
+ * @param {!WebGLSampler} sampler
+ * @param {number} pname
+ * @param {number} param
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.samplerParameteri = function(
+    sampler, pname, param) {};
+
+/**
+ * @param {!WebGLSampler} sampler
+ * @param {number} pname
+ * @param {number} param
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.samplerParameterf = function(
+    sampler, pname, param) {};
+
+/**
+ * @param {!WebGLSampler} sampler
+ * @param {number} pname
+ * @return {*}
+ * @nosideeffects
+ */
+WebGL2RenderingContext.prototype.getSamplerParameter = function(
+    sampler, pname) {};
+
+/* Sync objects */
+
+/**
+ * @param {number} condition
+ * @param {number} flags
+ * @return {?WebGLSync}
+ */
+WebGL2RenderingContext.prototype.fenceSync = function(condition, flags) {};
+
+/**
+ * @param {?WebGLSync} sync
+ * @return {boolean}
+ */
+WebGL2RenderingContext.prototype.isSync = function(sync) {};
+
+/**
+ * @param {?WebGLSync} sync
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.deleteSync = function(sync) {};
+
+/**
+ * @param {!WebGLSync} sync
+ * @param {number} flags
+ * @param {number} timeout
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.clientWaitSync = function(
+    sync, flags, timeout) {};
+
+/**
+ * @param {!WebGLSync} sync
+ * @param {number} flags
+ * @param {number} timeout
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.waitSync = function(sync, flags, timeout) {};
+
+/**
+ * @param {!WebGLSync} sync
+ * @param {number} pname
+ * @return {*}
+ */
+WebGL2RenderingContext.prototype.getSyncParameter = function(sync, pname) {};
+
+/* Transform Feedback */
+
+/**
+ * @return {?WebGLTransformFeedback}
+ */
+WebGL2RenderingContext.prototype.createTransformFeedback = function() {};
+
+/**
+ * @param {?WebGLTransformFeedback} tf
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.deleteTransformFeedback = function(tf) {};
+
+/**
+ * @param {?WebGLTransformFeedback} tf
+ * @return {boolean}
+ */
+WebGL2RenderingContext.prototype.isTransformFeedback = function(tf) {};
+
+/**
+ * @param {number} target
+ * @param {?WebGLTransformFeedback} tf
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.bindTransformFeedback = function(
+    target, tf) {};
+
+/**
+ * @param {number} primitiveMode
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.beginTransformFeedback = function(
+    primitiveMode) {};
+
+/**
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.endTransformFeedback = function() {};
+
+/**
+ * @param {!WebGLProgram} program
+ * @param {!Array<string>} varyings
+ * @param {number} bufferMode
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.transformFeedbackVaryings = function(
+    program, varyings, bufferMode) {};
+
+/**
+ * @param {!WebGLProgram} program
+ * @param {number} index
+ * @return {?WebGLActiveInfo}
+ * @nosideeffects
+ */
+WebGL2RenderingContext.prototype.getTransformFeedbackVarying = function(
+    program, index) {};
+
+/**
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.pauseTransformFeedback = function() {};
+
+/**
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.resumeTransformFeedback = function() {};
+
+/* Uniform Buffer Objects and Transform Feedback Buffers */
+
+/**
+ * @param {number} target
+ * @param {number} index
+ * @param {?WebGLBuffer} buffer
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.bindBufferBase = function(
+    target, index, buffer) {};
+
+/**
+ * @param {number} target
+ * @param {number} index
+ * @param {?WebGLBuffer} buffer
+ * @param {number} offset
+ * @param {number} size
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.bindBufferRange = function(
+    target, index, buffer, offset, size) {};
+
+/**
+ * @param {number} target
+ * @param {number} index
+ * @return {*}
+ */
+WebGL2RenderingContext.prototype.getIndexedParameter = function(
+    target, index) {};
+
+/**
+ * @param {!WebGLProgram} program
+ * @param {!Array<string>} uniformNames
+ * @return {!Array<number>}
+ */
+WebGL2RenderingContext.prototype.getUniformIndices = function(
+    program, uniformNames) {};
+
+/**
+ * @param {!WebGLProgram} program
+ * @param {!Array<number>} uniformIndices
+ * @param {number} pname
+ * @return {*}
+ */
+WebGL2RenderingContext.prototype.getActiveUniforms = function(
+    program, uniformIndices, pname) {};
+
+/**
+ * @param {!WebGLProgram} program
+ * @param {string} uniformBlockName
+ * @return {number}
+ * @nosideeffects
+ */
+WebGL2RenderingContext.prototype.getUniformBlockIndex = function(
+    program, uniformBlockName) {};
+
+/**
+ * @param {!WebGLProgram} program
+ * @param {number} uniformBlockIndex
+ * @param {number} pname
+ * @return {*}
+ */
+WebGL2RenderingContext.prototype.getActiveUniformBlockParameter = function(
+    program, uniformBlockIndex, pname) {};
+
+/**
+ * @param {!WebGLProgram} program
+ * @param {number} uniformBlockIndex
+ * @return {?string}
+ * @nosideeffects
+ */
+WebGL2RenderingContext.prototype.getActiveUniformBlockName = function(
+    program, uniformBlockIndex) {};
+
+/**
+ * @param {!WebGLProgram} program
+ * @param {number} uniformBlockIndex
+ * @param {number} uniformBlockBinding
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.uniformBlockBinding = function(
+    program, uniformBlockIndex, uniformBlockBinding) {};
+
+/* Vertex Array Objects */
+
+/**
+ * @return {?WebGLVertexArrayObject}
+ */
+WebGL2RenderingContext.prototype.createVertexArray = function() {};
+
+/**
+ * @param {?WebGLVertexArrayObject} vertexArray
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.deleteVertexArray = function(vertexArray) {};
+
+/**
+ * @param {?WebGLVertexArrayObject} vertexArray
+ * @return {boolean}
+ */
+WebGL2RenderingContext.prototype.isVertexArray = function(vertexArray) {};
+
+/**
+ * @param {?WebGLVertexArrayObject} array
+ * @return {undefined}
+ */
+WebGL2RenderingContext.prototype.bindVertexArray = function(array) {};
+
+
+/**
+ * @constructor
+ * @extends {WebGLObject}
+ */
+function WebGLQuery() {}
+
+
+/**
+ * @constructor
+ * @extends {WebGLObject}
+ */
+function WebGLSampler() {}
+
+
+/**
+ * @constructor
+ * @extends {WebGLObject}
+ */
+function WebGLSync() {}
+
+
+/**
+ * @constructor
+ * @extends {WebGLObject}
+ */
+function WebGLTransformFeedback() {}
+
+
+/**
+ * @constructor
+ * @extends {WebGLObject}
+ */
+function WebGLVertexArrayObject() {}
diff --git a/javascript/externs/web/webgl2_compute.js b/javascript/externs/web/webgl2_compute.js
new file mode 100644
index 000000000000..87c31d1febf5
--- /dev/null
+++ b/javascript/externs/web/webgl2_compute.js
@@ -0,0 +1,1609 @@
+/*
+ * Copyright 2019 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for WebGL functions as described at
+ * http://www.khronos.org/registry/webgl/specs/latest/
+ *
+ * This file is current up to the WebGL 2.0 Compute spec.
+ *
+ * This relies on webgl2.js and html5.js being included for WebGL2, Canvas and
+ * Typed Array support.
+ *
+ * @externs
+ */
+
+
+/**
+ * @constructor
+ * @extends {WebGL2RenderingContext}
+ * @see https://www.khronos.org/registry/webgl/specs/latest/2.0-compute/#webgl2-compute-context
+ */
+function WebGL2ComputeRenderingContext() {}
+
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.COMPUTE_SHADER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_COMPUTE_UNIFORM_BLOCKS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_COMPUTE_TEXTURE_IMAGE_UNITS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_COMPUTE_IMAGE_UNIFORMS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_COMPUTE_SHARED_MEMORY_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_COMPUTE_UNIFORM_COMPONENTS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_COMPUTE_ATOMIC_COUNTER_BUFFERS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_COMPUTE_ATOMIC_COUNTERS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_COMBINED_COMPUTE_UNIFORM_COMPONENTS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_COMPUTE_WORK_GROUP_INVOCATIONS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_COMPUTE_WORK_GROUP_COUNT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_COMPUTE_WORK_GROUP_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.COMPUTE_WORK_GROUP_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.DISPATCH_INDIRECT_BUFFER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.DISPATCH_INDIRECT_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.COMPUTE_SHADER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.DRAW_INDIRECT_BUFFER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.DRAW_INDIRECT_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_UNIFORM_LOCATIONS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.FRAMEBUFFER_DEFAULT_WIDTH;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.FRAMEBUFFER_DEFAULT_HEIGHT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.FRAMEBUFFER_DEFAULT_SAMPLES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.FRAMEBUFFER_DEFAULT_FIXED_SAMPLE_LOCATIONS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_FRAMEBUFFER_WIDTH;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_FRAMEBUFFER_HEIGHT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_FRAMEBUFFER_SAMPLES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.UNIFORM;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.UNIFORM_BLOCK;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.PROGRAM_INPUT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.PROGRAM_OUTPUT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.BUFFER_VARIABLE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.SHADER_STORAGE_BLOCK;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.ATOMIC_COUNTER_BUFFER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TRANSFORM_FEEDBACK_VARYING;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.ACTIVE_RESOURCES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_NAME_LENGTH;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_NUM_ACTIVE_VARIABLES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.NAME_LENGTH;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TYPE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.ARRAY_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.OFFSET;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.BLOCK_INDEX;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.ARRAY_STRIDE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MATRIX_STRIDE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.IS_ROW_MAJOR;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.ATOMIC_COUNTER_BUFFER_INDEX;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.BUFFER_DATA_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.NUM_ACTIVE_VARIABLES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.ACTIVE_VARIABLES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.REFERENCED_BY_VERTEX_SHADER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.REFERENCED_BY_FRAGMENT_SHADER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.REFERENCED_BY_COMPUTE_SHADER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TOP_LEVEL_ARRAY_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TOP_LEVEL_ARRAY_STRIDE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.LOCATION;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.VERTEX_SHADER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.FRAGMENT_SHADER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.ALL_SHADER_BITS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.ATOMIC_COUNTER_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.ATOMIC_COUNTER_BUFFER_START;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.ATOMIC_COUNTER_BUFFER_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_VERTEX_ATOMIC_COUNTER_BUFFERS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_FRAGMENT_ATOMIC_COUNTER_BUFFERS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_COMBINED_ATOMIC_COUNTER_BUFFERS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_VERTEX_ATOMIC_COUNTERS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_FRAGMENT_ATOMIC_COUNTERS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_COMBINED_ATOMIC_COUNTERS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_ATOMIC_COUNTER_BUFFER_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_ATOMIC_COUNTER_BUFFER_BINDINGS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.ACTIVE_ATOMIC_COUNTER_BUFFERS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.UNSIGNED_INT_ATOMIC_COUNTER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_IMAGE_UNITS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_VERTEX_IMAGE_UNIFORMS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_FRAGMENT_IMAGE_UNIFORMS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_COMBINED_IMAGE_UNIFORMS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.IMAGE_BINDING_NAME;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.IMAGE_BINDING_LEVEL;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.IMAGE_BINDING_LAYERED;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.IMAGE_BINDING_LAYER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.IMAGE_BINDING_ACCESS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.IMAGE_BINDING_FORMAT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.VERTEX_ATTRIB_ARRAY_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.ELEMENT_ARRAY_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.UNIFORM_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_FETCH_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.SHADER_IMAGE_ACCESS_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.COMMAND_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.PIXEL_BUFFER_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_UPDATE_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.BUFFER_UPDATE_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.FRAMEBUFFER_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TRANSFORM_FEEDBACK_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.ATOMIC_COUNTER_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.SHADER_STORAGE_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.ALL_BARRIER_BITS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.IMAGE_2D;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.IMAGE_3D;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.IMAGE_CUBE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.IMAGE_2D_ARRAY;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.INT_IMAGE_2D;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.INT_IMAGE_3D;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.INT_IMAGE_CUBE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.INT_IMAGE_2D_ARRAY;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.UNSIGNED_INT_IMAGE_2D;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.UNSIGNED_INT_IMAGE_3D;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.UNSIGNED_INT_IMAGE_CUBE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.UNSIGNED_INT_IMAGE_2D_ARRAY;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.IMAGE_FORMAT_COMPATIBILITY_TYPE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.IMAGE_FORMAT_COMPATIBILITY_BY_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.IMAGE_FORMAT_COMPATIBILITY_BY_CLASS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.READ_ONLY;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.WRITE_ONLY;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.READ_WRITE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.SHADER_STORAGE_BUFFER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.SHADER_STORAGE_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.SHADER_STORAGE_BUFFER_START;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.SHADER_STORAGE_BUFFER_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_VERTEX_SHADER_STORAGE_BLOCKS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_FRAGMENT_SHADER_STORAGE_BLOCKS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_COMPUTE_SHADER_STORAGE_BLOCKS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_COMBINED_SHADER_STORAGE_BLOCKS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_SHADER_STORAGE_BUFFER_BINDINGS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_SHADER_STORAGE_BLOCK_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.SHADER_STORAGE_BUFFER_OFFSET_ALIGNMENT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_COMBINED_SHADER_OUTPUT_RESOURCES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.DEPTH_STENCIL_TEXTURE_MODE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.STENCIL_INDEX;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MIN_PROGRAM_TEXTURE_GATHER_OFFSET;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_PROGRAM_TEXTURE_GATHER_OFFSET;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.SAMPLE_POSITION;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.SAMPLE_MASK;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.SAMPLE_MASK_VALUE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_2D_MULTISAMPLE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_SAMPLE_MASK_WORDS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_COLOR_TEXTURE_SAMPLES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_DEPTH_TEXTURE_SAMPLES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_INTEGER_SAMPLES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_BINDING_2D_MULTISAMPLE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_SAMPLES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_FIXED_SAMPLE_LOCATIONS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_WIDTH;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_HEIGHT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_DEPTH;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_INTERNAL_FORMAT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_RED_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_GREEN_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_BLUE_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_ALPHA_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_DEPTH_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_STENCIL_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_SHARED_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_RED_TYPE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_GREEN_TYPE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_BLUE_TYPE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_ALPHA_TYPE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_DEPTH_TYPE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.TEXTURE_COMPRESSED;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.SAMPLER_2D_MULTISAMPLE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.INT_SAMPLER_2D_MULTISAMPLE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.UNSIGNED_INT_SAMPLER_2D_MULTISAMPLE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.VERTEX_ATTRIB_BINDING;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.VERTEX_ATTRIB_RELATIVE_OFFSET;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.VERTEX_BINDING_DIVISOR;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.VERTEX_BINDING_OFFSET;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.VERTEX_BINDING_STRIDE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.VERTEX_BINDING_BUFFER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_VERTEX_ATTRIB_RELATIVE_OFFSET;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_VERTEX_ATTRIB_BINDINGS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.MAX_VERTEX_ATTRIB_STRIDE;
+
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.COMPUTE_SHADER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_COMPUTE_UNIFORM_BLOCKS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_COMPUTE_TEXTURE_IMAGE_UNITS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_COMPUTE_IMAGE_UNIFORMS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_COMPUTE_SHARED_MEMORY_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_COMPUTE_UNIFORM_COMPONENTS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_COMPUTE_ATOMIC_COUNTER_BUFFERS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_COMPUTE_ATOMIC_COUNTERS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_COMBINED_COMPUTE_UNIFORM_COMPONENTS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_COMPUTE_WORK_GROUP_INVOCATIONS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_COMPUTE_WORK_GROUP_COUNT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_COMPUTE_WORK_GROUP_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.COMPUTE_WORK_GROUP_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.DISPATCH_INDIRECT_BUFFER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.DISPATCH_INDIRECT_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.COMPUTE_SHADER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.DRAW_INDIRECT_BUFFER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.DRAW_INDIRECT_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_UNIFORM_LOCATIONS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.FRAMEBUFFER_DEFAULT_WIDTH;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.FRAMEBUFFER_DEFAULT_HEIGHT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.FRAMEBUFFER_DEFAULT_SAMPLES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype
+    .FRAMEBUFFER_DEFAULT_FIXED_SAMPLE_LOCATIONS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_FRAMEBUFFER_WIDTH;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_FRAMEBUFFER_HEIGHT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_FRAMEBUFFER_SAMPLES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.UNIFORM;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.UNIFORM_BLOCK;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.PROGRAM_INPUT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.PROGRAM_OUTPUT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.BUFFER_VARIABLE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.SHADER_STORAGE_BLOCK;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.ATOMIC_COUNTER_BUFFER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TRANSFORM_FEEDBACK_VARYING;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.ACTIVE_RESOURCES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_NAME_LENGTH;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_NUM_ACTIVE_VARIABLES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.NAME_LENGTH;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TYPE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.ARRAY_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.OFFSET;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.BLOCK_INDEX;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.ARRAY_STRIDE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MATRIX_STRIDE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.IS_ROW_MAJOR;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.ATOMIC_COUNTER_BUFFER_INDEX;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.BUFFER_DATA_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.NUM_ACTIVE_VARIABLES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.ACTIVE_VARIABLES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.REFERENCED_BY_VERTEX_SHADER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.REFERENCED_BY_FRAGMENT_SHADER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.REFERENCED_BY_COMPUTE_SHADER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TOP_LEVEL_ARRAY_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TOP_LEVEL_ARRAY_STRIDE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.LOCATION;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.VERTEX_SHADER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.FRAGMENT_SHADER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.ALL_SHADER_BITS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.ATOMIC_COUNTER_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.ATOMIC_COUNTER_BUFFER_START;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.ATOMIC_COUNTER_BUFFER_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_VERTEX_ATOMIC_COUNTER_BUFFERS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_FRAGMENT_ATOMIC_COUNTER_BUFFERS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_COMBINED_ATOMIC_COUNTER_BUFFERS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_VERTEX_ATOMIC_COUNTERS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_FRAGMENT_ATOMIC_COUNTERS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_COMBINED_ATOMIC_COUNTERS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_ATOMIC_COUNTER_BUFFER_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_ATOMIC_COUNTER_BUFFER_BINDINGS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.ACTIVE_ATOMIC_COUNTER_BUFFERS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.UNSIGNED_INT_ATOMIC_COUNTER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_IMAGE_UNITS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_VERTEX_IMAGE_UNIFORMS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_FRAGMENT_IMAGE_UNIFORMS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_COMBINED_IMAGE_UNIFORMS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.IMAGE_BINDING_NAME;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.IMAGE_BINDING_LEVEL;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.IMAGE_BINDING_LAYERED;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.IMAGE_BINDING_LAYER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.IMAGE_BINDING_ACCESS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.IMAGE_BINDING_FORMAT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.VERTEX_ATTRIB_ARRAY_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.ELEMENT_ARRAY_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.UNIFORM_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_FETCH_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.SHADER_IMAGE_ACCESS_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.COMMAND_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.PIXEL_BUFFER_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_UPDATE_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.BUFFER_UPDATE_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.FRAMEBUFFER_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TRANSFORM_FEEDBACK_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.ATOMIC_COUNTER_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.SHADER_STORAGE_BARRIER_BIT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.ALL_BARRIER_BITS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.IMAGE_2D;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.IMAGE_3D;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.IMAGE_CUBE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.IMAGE_2D_ARRAY;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.INT_IMAGE_2D;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.INT_IMAGE_3D;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.INT_IMAGE_CUBE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.INT_IMAGE_2D_ARRAY;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.UNSIGNED_INT_IMAGE_2D;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.UNSIGNED_INT_IMAGE_3D;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.UNSIGNED_INT_IMAGE_CUBE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.UNSIGNED_INT_IMAGE_2D_ARRAY;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.IMAGE_FORMAT_COMPATIBILITY_TYPE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.IMAGE_FORMAT_COMPATIBILITY_BY_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.IMAGE_FORMAT_COMPATIBILITY_BY_CLASS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.READ_ONLY;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.WRITE_ONLY;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.READ_WRITE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.SHADER_STORAGE_BUFFER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.SHADER_STORAGE_BUFFER_BINDING;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.SHADER_STORAGE_BUFFER_START;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.SHADER_STORAGE_BUFFER_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_VERTEX_SHADER_STORAGE_BLOCKS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_FRAGMENT_SHADER_STORAGE_BLOCKS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_COMPUTE_SHADER_STORAGE_BLOCKS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_COMBINED_SHADER_STORAGE_BLOCKS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_SHADER_STORAGE_BUFFER_BINDINGS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_SHADER_STORAGE_BLOCK_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.SHADER_STORAGE_BUFFER_OFFSET_ALIGNMENT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_COMBINED_SHADER_OUTPUT_RESOURCES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.DEPTH_STENCIL_TEXTURE_MODE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.STENCIL_INDEX;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MIN_PROGRAM_TEXTURE_GATHER_OFFSET;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_PROGRAM_TEXTURE_GATHER_OFFSET;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.SAMPLE_POSITION;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.SAMPLE_MASK;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.SAMPLE_MASK_VALUE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_2D_MULTISAMPLE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_SAMPLE_MASK_WORDS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_COLOR_TEXTURE_SAMPLES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_DEPTH_TEXTURE_SAMPLES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_INTEGER_SAMPLES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_BINDING_2D_MULTISAMPLE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_SAMPLES;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_FIXED_SAMPLE_LOCATIONS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_WIDTH;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_HEIGHT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_DEPTH;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_INTERNAL_FORMAT;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_RED_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_GREEN_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_BLUE_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_ALPHA_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_DEPTH_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_STENCIL_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_SHARED_SIZE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_RED_TYPE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_GREEN_TYPE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_BLUE_TYPE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_ALPHA_TYPE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_DEPTH_TYPE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.TEXTURE_COMPRESSED;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.SAMPLER_2D_MULTISAMPLE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.INT_SAMPLER_2D_MULTISAMPLE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.UNSIGNED_INT_SAMPLER_2D_MULTISAMPLE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.VERTEX_ATTRIB_BINDING;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.VERTEX_ATTRIB_RELATIVE_OFFSET;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.VERTEX_BINDING_DIVISOR;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.VERTEX_BINDING_OFFSET;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.VERTEX_BINDING_STRIDE;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.VERTEX_BINDING_BUFFER;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_VERTEX_ATTRIB_RELATIVE_OFFSET;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_VERTEX_ATTRIB_BINDINGS;
+
+/** @const {number} */
+WebGL2ComputeRenderingContext.prototype.MAX_VERTEX_ATTRIB_STRIDE;
+
+
+/**
+ * @param {number} num_groups_x
+ * @param {number} num_groups_y
+ * @param {number} num_groups_z
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.dispatchCompute = function(
+    num_groups_x, num_groups_y, num_groups_z) {};
+
+/**
+ * @param {number} offset
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.dispatchComputeIndirect = function(
+    offset) {};
+
+/**
+ * @param {number} mode
+ * @param {number} offset
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.drawArraysIndirect = function(
+    mode, offset) {};
+
+/**
+ * @param {number} mode
+ * @param {number} type
+ * @param {number} offset
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.drawElementsIndirect = function(
+    mode, type, offset) {};
+
+/**
+ * @param {number} target
+ * @param {number} pname
+ * @param {number} param
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.framebufferParameter = function(
+    target, pname, param) {};
+
+/**
+ * @param {number} target
+ * @param {number} pname
+ * @return {*}
+ */
+WebGL2ComputeRenderingContext.prototype.getFramebufferParameter = function(
+    target, pname) {};
+
+/**
+ * @param {!WebGLProgram} program
+ * @param {number} programInterface
+ * @param {number} pname
+ * @return {*}
+ */
+WebGL2ComputeRenderingContext.prototype.getProgramInterfaceParameter = function(
+    program, programInterface, pname) {};
+
+/**
+ * @param {!WebGLProgram} program
+ * @param {number} programInterface
+ * @param {number} index
+ * @param {!Array<number>} props
+ * @return {?Array<*>}
+ */
+WebGL2ComputeRenderingContext.prototype.getProgramResource = function(
+    program, programInterface, index, props) {};
+
+/**
+ * @param {!WebGLProgram} program
+ * @param {number} programInterface
+ * @param {string} name
+ * @return {number}
+ */
+WebGL2ComputeRenderingContext.prototype.getProgramResourceIndex = function(
+    program, programInterface, name) {};
+
+/**
+ * @param {!WebGLProgram} program
+ * @param {number} programInterface
+ * @param {number} index
+ * @return {?string}
+ */
+WebGL2ComputeRenderingContext.prototype.getProgramResourceName = function(
+    program, programInterface, index) {};
+
+/**
+ * @param {!WebGLProgram} program
+ * @param {number} programInterface
+ * @param {string} name
+ * @return {*}
+ */
+WebGL2ComputeRenderingContext.prototype.getProgramResourceLocation = function(
+    program, programInterface, name) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} v0
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform1i = function(
+    program, location, v0) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} v0
+ * @param {number} v1
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform2i = function(
+    program, location, v0, v1) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} v0
+ * @param {number} v1
+ * @param {number} v2
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform3i = function(
+    program, location, v0, v1, v2) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} v0
+ * @param {number} v1
+ * @param {number} v2
+ * @param {number} v3
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform4i = function(
+    program, location, v0, v1, v2, v3) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} v0
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform1ui = function(
+    program, location, v0) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} v0
+ * @param {number} v1
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform2ui = function(
+    program, location, v0, v1) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} v0
+ * @param {number} v1
+ * @param {number} v2
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform3ui = function(
+    program, location, v0, v1, v2) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} v0
+ * @param {number} v1
+ * @param {number} v2
+ * @param {number} v3
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform4ui = function(
+    program, location, v0, v1, v2, v3) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} v0
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform1f = function(
+    program, location, v0) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} v0
+ * @param {number} v1
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform2f = function(
+    program, location, v0, v1) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} v0
+ * @param {number} v1
+ * @param {number} v2
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform3f = function(
+    program, location, v0, v1, v2) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} v0
+ * @param {number} v1
+ * @param {number} v2
+ * @param {number} v3
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform4f = function(
+    program, location, v0, v1, v2, v3) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {!Int32Array|!Array<number>|!Array<boolean>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform1iv = function(
+    program, location, count, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {!Int32Array|!Array<number>|!Array<boolean>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform2iv = function(
+    program, location, count, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {!Int32Array|!Array<number>|!Array<boolean>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform3iv = function(
+    program, location, count, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {!Int32Array|!Array<number>|!Array<boolean>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform4iv = function(
+    program, location, count, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {!Uint32Array|!Array<number>|!Array<boolean>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform1uiv = function(
+    program, location, count, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {!Uint32Array|!Array<number>|!Array<boolean>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform2uiv = function(
+    program, location, count, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {!Uint32Array|!Array<number>|!Array<boolean>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform3uiv = function(
+    program, location, count, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {!Uint32Array|!Array<number>|!Array<boolean>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform4uiv = function(
+    program, location, count, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {!Float32Array|!Array<number>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform1fv = function(
+    program, location, count, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {!Float32Array|!Array<number>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform2fv = function(
+    program, location, count, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {!Float32Array|!Array<number>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform3fv = function(
+    program, location, count, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {!Float32Array|!Array<number>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniform4fv = function(
+    program, location, count, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {boolean} transpose
+ * @param {!Float32Array|!Array<number>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniformMatrix2fv = function(
+    program, location, count, transpose, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {boolean} transpose
+ * @param {!Float32Array|!Array<number>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniformMatrix3fv = function(
+    program, location, count, transpose, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {boolean} transpose
+ * @param {!Float32Array|!Array<number>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniformMatrix4fv = function(
+    program, location, count, transpose, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {boolean} transpose
+ * @param {!Float32Array|!Array<number>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniformMatrix2x3fv = function(
+    program, location, count, transpose, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {boolean} transpose
+ * @param {!Float32Array|!Array<number>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniformMatrix3x2fv = function(
+    program, location, count, transpose, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {boolean} transpose
+ * @param {!Float32Array|!Array<number>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniformMatrix2x4fv = function(
+    program, location, count, transpose, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {boolean} transpose
+ * @param {!Float32Array|!Array<number>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniformMatrix4x2fv = function(
+    program, location, count, transpose, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {boolean} transpose
+ * @param {!Float32Array|!Array<number>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniformMatrix3x4fv = function(
+    program, location, count, transpose, data) {};
+
+/**
+ * @param {?WebGLProgram} program
+ * @param {?WebGLUniformLocation} location
+ * @param {number} count
+ * @param {boolean} transpose
+ * @param {!Float32Array|!Array<number>} data
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.programUniformMatrix4x3fv = function(
+    program, location, count, transpose, data) {};
+
+/**
+ * @param {number} unit
+ * @param {?WebGLTexture} texture
+ * @param {number} level
+ * @param {boolean} layered
+ * @param {number} layer
+ * @param {number} access
+ * @param {number} format
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.bindImageTexture = function(
+    unit, texture, level, layered, layer, access, format) {};
+
+/**
+ * @param {number} barriers
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.memoryBarrier = function(barriers) {};
+
+/**
+ * @param {number} barriers
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.memoryBarrierByRegion = function(
+    barriers) {};
+
+/**
+ * @param {number} target
+ * @param {number} samples
+ * @param {number} internalformat
+ * @param {number} width
+ * @param {number} height
+ * @param {boolean} fixedsamplelocations
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.texStorage2DMultisample = function(
+    target, samples, internalformat, width, height, fixedsamplelocations) {};
+
+/**
+ * @param {number} target
+ * @param {number} level
+ * @param {number} pname
+ * @return {*}
+ */
+WebGL2ComputeRenderingContext.prototype.getTexLevelParameter = function(
+    target, level, pname) {};
+
+/**
+ * @param {number} pname
+ * @param {number} index
+ * @return {*}
+ */
+WebGL2ComputeRenderingContext.prototype.getMultisample = function(
+    pname, index) {};
+
+/**
+ * @param {number} index
+ * @param {number} mask
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.sampleMask = function(index, mask) {};
+
+/**
+ * @param {number} bindingindex
+ * @param {?WebGLBuffer} buffer
+ * @param {number} offset
+ * @param {number} stride
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.bindVertexBuffer = function(
+    bindingindex, buffer, offset, stride) {};
+
+/**
+ * @param {number} attribindex
+ * @param {number} size
+ * @param {number} type
+ * @param {boolean} normalized
+ * @param {number} relativeoffset
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.vertexAttribFormat = function(
+    attribindex, size, type, normalized, relativeoffset) {};
+
+/**
+ * @param {number} attribindex
+ * @param {number} size
+ * @param {number} type
+ * @param {number} relativeoffset
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.vertexAttribIFormat = function(
+    attribindex, size, type, relativeoffset) {};
+
+/**
+ * @param {number} attribindex
+ * @param {number} bindingindex
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.vertexAttribBinding = function(
+    attribindex, bindingindex) {};
+
+/**
+ * @param {number} bindingindex
+ * @param {number} divisor
+ * @return {undefined}
+ */
+WebGL2ComputeRenderingContext.prototype.vertexBindingDivisor = function(
+    bindingindex, divisor) {};
diff --git a/javascript/externs/web/whatwg_console.js b/javascript/externs/web/whatwg_console.js
new file mode 100644
index 000000000000..a306a2eea90f
--- /dev/null
+++ b/javascript/externs/web/whatwg_console.js
@@ -0,0 +1,152 @@
+/*
+ * Copyright 2019 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Definitions for console debugging facilities.
+ *     https://console.spec.whatwg.org/
+ * @externs
+ */
+
+/**
+ * @constructor
+ * @see https://console.spec.whatwg.org/
+ */
+function Console() {};
+
+/**
+ * If condition is false, perform Logger("error", data).
+ * @param {*} condition
+ * @param {...*} var_data
+ * @return {undefined}
+ */
+Console.prototype.assert = function(condition, var_data) {};
+
+/**
+ * @return {undefined}
+ */
+Console.prototype.clear = function() {};
+
+/**
+ * @param {...*} var_data
+ * @return {undefined}
+ */
+Console.prototype.debug = function(var_data) {};
+
+/**
+ * @param {...*} var_data
+ * @return {undefined}
+ */
+Console.prototype.error = function(var_data) {};
+
+/**
+ * @param {...*} var_data
+ * @return {undefined}
+ */
+Console.prototype.info = function(var_data) {};
+
+/**
+ * @param {...*} var_data
+ * @return {undefined}
+ */
+Console.prototype.log = function(var_data) {};
+
+/**
+ * @param {!Object} tabularData
+ * @param {*=} properties
+ * @return {undefined}
+ */
+Console.prototype.table = function(tabularData, properties) {};
+
+/**
+ * @param {...*} var_data
+ * @return {undefined}
+ */
+Console.prototype.trace = function(var_data) {};
+
+/**
+ * @param {...*} var_data
+ * @return {undefined}
+ */
+Console.prototype.warn = function(var_data) {};
+
+/**
+ * @param {*} item
+ * @return {undefined}
+ */
+Console.prototype.dir = function(item) {};
+
+/**
+ * @param {...*} var_data
+ * @return {undefined}
+ */
+Console.prototype.dirxml = function(var_data) {};
+
+/**
+ * @param {string=} label
+ * @return {undefined}
+ */
+Console.prototype.count = function(label) {};
+
+/**
+ * @param {string=} label
+ * @return {undefined}
+ */
+Console.prototype.countReset = function(label) {};
+
+/**
+ * @param {...*} var_data
+ * @return {undefined}
+ */
+Console.prototype.group = function(var_data) {};
+
+/**
+ * @param {...*} var_data
+ * @return {undefined}
+ */
+Console.prototype.groupCollapsed = function(var_data) {};
+
+/**
+ * @return {undefined}
+ */
+Console.prototype.groupEnd = function() {};
+
+/**
+ * @param {string} label
+ * @return {undefined}
+ */
+Console.prototype.time = function(label) {};
+
+/**
+ * @param {string} label
+ * @param {...*} data
+ * @return {undefined}
+ */
+Console.prototype.timeLog = function(label, data) {};
+
+/**
+ * @param {string} label
+ * @return {undefined}
+ */
+Console.prototype.timeEnd = function(label) {};
+
+/** @type {!Console} */
+Window.prototype.console;
+
+/**
+ * @type {!Console}
+ * @suppress {duplicate}
+ */
+var console;
diff --git a/javascript/externs/web/wicg_file_system_access.js b/javascript/externs/web/wicg_file_system_access.js
new file mode 100644
index 000000000000..9fe8f922af70
--- /dev/null
+++ b/javascript/externs/web/wicg_file_system_access.js
@@ -0,0 +1,331 @@
+/*
+ * Copyright 2020 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * File System Access
+ * Draft Community Group Report, 18 November 2020
+ * @externs
+ * @see https://wicg.github.io/file-system-access/
+ */
+
+
+
+/**
+ * @record
+ * @struct
+ * @see https://wicg.github.io/file-system-access/#dictdef-filesystemhandlepermissiondescriptor
+ */
+var FileSystemHandlePermissionDescriptor = function() {};
+
+/** @type {undefined|string} */
+FileSystemHandlePermissionDescriptor.prototype.mode;
+
+
+/**
+ * @typedef {string}
+ * @see https://wicg.github.io/file-system-access/#enumdef-filesystemhandlekind
+ */
+var FileSystemHandleKind;
+
+
+/**
+ * @interface
+ * @see https://wicg.github.io/file-system-access/#api-filesystemhandle
+ */
+var FileSystemHandle = function() {};
+
+/** @const {!FileSystemHandleKind} */
+FileSystemHandle.prototype.kind;
+
+/** @const {string} */
+FileSystemHandle.prototype.name;
+
+/**
+ * @param {!FileSystemHandle} other
+ * @return {!Promise<boolean>}
+ */
+FileSystemHandle.prototype.isSameEntry = function(other) {};
+
+/**
+ * @param {!FileSystemHandlePermissionDescriptor=} opt_descriptor
+ * @return {!Promise<!PermissionState>}
+ */
+FileSystemHandle.prototype.queryPermission = function(opt_descriptor) {};
+
+/**
+ * @param {!FileSystemHandlePermissionDescriptor=} opt_descriptor
+ * @return {!Promise<!PermissionState>}
+ */
+FileSystemHandle.prototype.requestPermission = function(opt_descriptor) {};
+
+
+/**
+ * @record
+ * @struct
+ * @see https://wicg.github.io/file-system-access/#dictdef-filesystemcreatewritableoptions
+ */
+var FileSystemCreateWritableOptions = function() {};
+
+/** @type {undefined|boolean} */
+FileSystemCreateWritableOptions.prototype.keepExistingData;
+
+
+/**
+ * @interface
+ * @extends {FileSystemHandle}
+ * @see https://wicg.github.io/file-system-access/#api-filesystemfilehandle
+ */
+var FileSystemFileHandle = function() {};
+
+/**
+ * @return {!Promise<!File>}
+ */
+FileSystemFileHandle.prototype.getFile = function() {};
+
+/**
+ * @param {!FileSystemCreateWritableOptions=} opt_options
+ * @return {!Promise<!FileSystemWritableFileStream>}
+ */
+FileSystemFileHandle.prototype.createWritable = function(opt_options) {};
+
+
+/**
+ * @record
+ * @struct
+ * @see https://wicg.github.io/file-system-access/#dictdef-filesystemgetfileoptions
+ */
+var FileSystemGetFileOptions = function() {};
+
+/** @type {undefined|boolean} */
+FileSystemGetFileOptions.prototype.create;
+
+
+/**
+ * @record
+ * @struct
+ * @see https://wicg.github.io/file-system-access/#dictdef-filesystemgetdirectoryoptions
+ */
+var FileSystemGetDirectoryOptions = function() {};
+
+/** @type {undefined|boolean} */
+FileSystemGetDirectoryOptions.prototype.create;
+
+
+/**
+ * @record
+ * @struct
+ * @see https://wicg.github.io/file-system-access/#dictdef-filesystemremoveoptions
+ */
+var FileSystemRemoveOptions = function() {};
+
+/** @type {undefined|boolean} */
+FileSystemRemoveOptions.prototype.recursive;
+
+
+/**
+ * @interface
+ * @extends {FileSystemHandle}
+ * @extends {AsyncIterable<!Array<string|!FileSystemHandle>>}
+ * @see https://wicg.github.io/file-system-access/#api-filesystemdirectoryhandle
+ * @see https://wicg.github.io/file-system-access/#api-filesystemdirectoryhandle-asynciterable
+ */
+var FileSystemDirectoryHandle = function() {};
+
+/**
+ * @param {string} name
+ * @param {!FileSystemGetFileOptions=} opt_options
+ * @return {!Promise<!FileSystemFileHandle>}
+ */
+FileSystemDirectoryHandle.prototype.getFileHandle = function(name, opt_options) {};
+
+/**
+ * @param {string} name
+ * @param {!FileSystemGetDirectoryOptions=} opt_options
+ * @return {!Promise<!FileSystemDirectoryHandle>}
+ */
+FileSystemDirectoryHandle.prototype.getDirectoryHandle = function(name, opt_options) {};
+
+/**
+ * @param {string} name
+ * @param {!FileSystemRemoveOptions=} opt_options
+ * @return {!Promise<void>}
+ */
+FileSystemDirectoryHandle.prototype.removeEntry = function(name, opt_options) {};
+
+/**
+ * @param {!FileSystemHandle} possibleDescendant
+ * @return {!Promise<?Array<string>>}
+ */
+FileSystemDirectoryHandle.prototype.resolve = function(possibleDescendant) {};
+
+/**
+ * @return {!AsyncIterable<!Array<string|!FileSystemHandle>>}
+ * @see https://wicg.github.io/file-system-access/#api-filesystemdirectoryhandle-asynciterable
+ */
+FileSystemDirectoryHandle.prototype.entries = function() {};
+
+/**
+ * @return {!AsyncIterable<!FileSystemHandle>}
+ * @see https://wicg.github.io/file-system-access/#api-filesystemdirectoryhandle-asynciterable
+ */
+FileSystemDirectoryHandle.prototype.values = function() {};
+
+/**
+ * @return {!AsyncIterable<string>}
+ * @see https://wicg.github.io/file-system-access/#api-filesystemdirectoryhandle-asynciterable
+ */
+FileSystemDirectoryHandle.prototype.keys = function() {};
+
+
+/**
+ * @typedef {string}
+ * @see https://wicg.github.io/file-system-access/#enumdef-writecommandtype
+ */
+var WriteCommandType;
+
+
+/**
+ * @record
+ * @struct
+ * @see https://wicg.github.io/file-system-access/#dictdef-writeparams
+ */
+var WriteParams = function() {};
+
+/** @type {!WriteCommandType} */
+WriteParams.prototype.type;
+
+/** @type {undefined|?number} */
+WriteParams.prototype.size;
+
+/** @type {undefined|?number} */
+WriteParams.prototype.position;
+
+/** @type {undefined|!BufferSource|!Blob|?string} */
+WriteParams.prototype.data;
+
+
+/**
+ * @typedef {!BufferSource|!Blob|string|!WriteParams}
+ * @see https://wicg.github.io/file-system-access/#typedefdef-filesystemwritechunktype
+ */
+var FileSystemWriteChunkType;
+
+
+/**
+ * @constructor
+ * @extends {WritableStream}
+ * @see https://wicg.github.io/file-system-access/#filesystemwritablefilestream
+ */
+var FileSystemWritableFileStream = function() {};
+
+/**
+ * @param {!FileSystemWriteChunkType} data
+ * @return {!Promise<void>}
+ */
+FileSystemWritableFileStream.prototype.write = function(data) {};
+
+/**
+ * @param {number} position
+ * @return {!Promise<void>}
+ */
+FileSystemWritableFileStream.prototype.seek = function(position) {};
+
+/**
+ * @param {number} size
+ * @return {!Promise<void>}
+ */
+FileSystemWritableFileStream.prototype.truncate = function(size) {};
+
+
+/**
+ * @record
+ * @struct
+ * @see https://wicg.github.io/file-system-access/#dictdef-filepickeraccepttype
+ */
+var FilePickerAcceptType = function() {};
+
+/** @type {undefined|string} */
+FilePickerAcceptType.prototype.description;
+
+/** @type {undefined|!Object<string,(string|!Array<string>)>} */
+FilePickerAcceptType.prototype.accept;
+
+
+/**
+ * @record
+ * @struct
+ * @see https://wicg.github.io/file-system-access/#dictdef-filepickeroptions
+ */
+var FilePickerOptions = function() {};
+
+/** @type {undefined|!Array<!FilePickerAcceptType>} */
+FilePickerOptions.prototype.types;
+
+/** @type {undefined|boolean} */
+FilePickerOptions.prototype.excludeAcceptAllOption;
+
+
+/**
+ * @record
+ * @struct
+ * @extends {FilePickerOptions}
+ * @see https://wicg.github.io/file-system-access/#dictdef-openfilepickeroptions
+ */
+var OpenFilePickerOptions = function() {};
+
+/** @type {undefined|boolean} */
+OpenFilePickerOptions.prototype.multiple;
+
+
+/**
+ * @record
+ * @struct
+ * @extends {FilePickerOptions}
+ * @see https://wicg.github.io/file-system-access/#dictdef-savefilepickeroptions
+ */
+var SaveFilePickerOptions = function() {};
+
+
+/**
+ * @record
+ * @struct
+ * @see https://wicg.github.io/file-system-access/#dictdef-directorypickeroptions
+ */
+var DirectoryPickerOptions = function() {};
+
+
+/**
+ * @param {!OpenFilePickerOptions=} opt_options
+ * @return {!Promise<!Array<!FileSystemFileHandle>>}
+ * @see https://wicg.github.io/file-system-access/#local-filesystem
+ */
+Window.prototype.showOpenFilePicker = function(opt_options) {};
+
+
+/**
+ * @param {!SaveFilePickerOptions=} opt_options
+ * @return {!Promise<!FileSystemFileHandle>}
+ * @see https://wicg.github.io/file-system-access/#local-filesystem
+ */
+Window.prototype.showSaveFilePicker = function(opt_options) {};
+
+
+/**
+ * @param {!DirectoryPickerOptions=} opt_options
+ * @return {!Promise<!FileSystemDirectoryHandle>}
+ * @see https://wicg.github.io/file-system-access/#local-filesystem
+ */
+Window.prototype.showDirectoryPicker = function(opt_options) {};
diff --git a/javascript/externs/web/wicg_floc.js b/javascript/externs/web/wicg_floc.js
new file mode 100644
index 000000000000..5afc775a64a1
--- /dev/null
+++ b/javascript/externs/web/wicg_floc.js
@@ -0,0 +1,27 @@
+/*
+ * Copyright 2008 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview The spec of FLoC interface.
+ * @see https://github.com/WICG/floc
+ * @externs
+ */
+
+/**
+ * @return {!Promise<string>}
+ * @see https://github.com/WICG/floc
+ */
+Document.prototype.interestCohort = function() {};
diff --git a/javascript/externs/web/wicg_resizeobserver.js b/javascript/externs/web/wicg_resizeobserver.js
new file mode 100644
index 000000000000..94fa3d1c3046
--- /dev/null
+++ b/javascript/externs/web/wicg_resizeobserver.js
@@ -0,0 +1,77 @@
+/*
+ * Copyright 2020 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/**
+ * @fileoverview The current draft spec of ResizeObserver.
+ * @see https://wicg.github.io/ResizeObserver/
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserver
+ * @externs
+ */
+
+/**
+ * @typedef {function(!Array<!ResizeObserverEntry>, !ResizeObserver)}
+ */
+var ResizeObserverCallback;
+
+/**
+ * @typedef {{box: string}}
+ */
+var ResizeObserverOptions;
+
+/**
+ * @constructor
+ * @param {!ResizeObserverCallback} callback
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserver/ResizeObserver
+ */
+function ResizeObserver(callback) {}
+
+/**
+ * @param {!Element} target
+ * @param {!ResizeObserverOptions=} opt_options
+ * @return {void}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserver/observe
+ */
+ResizeObserver.prototype.observe = function(target, opt_options) {};
+
+/**
+ * @param {!Element} target
+ * @return {void}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserver/unobserve
+ */
+ResizeObserver.prototype.unobserve = function(target) {};
+
+/**
+ * @return {void}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserver/disconnect
+ */
+ResizeObserver.prototype.disconnect = function() {};
+
+/**
+ * @interface
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserverEntry
+ */
+function ResizeObserverEntry() {}
+
+/**
+ * @const {!Element}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserverEntry/target
+ */
+ResizeObserverEntry.prototype.target;
+
+/**
+ * @const {!DOMRectReadOnly}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserverEntry/contentRect
+ */
+ResizeObserverEntry.prototype.contentRect;
diff --git a/javascript/externs/web/wicg_trust_token.js b/javascript/externs/web/wicg_trust_token.js
new file mode 100644
index 000000000000..bb048f6d3ead
--- /dev/null
+++ b/javascript/externs/web/wicg_trust_token.js
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2008 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview The spec of Trust Token interface.
+ * @see https://github.com/WICG/trust-token-api
+ * @externs
+ */
+
+/**
+ * Trust Tokens operation (issuance, signing, and redemption) is specified via
+ * an instance of the following parameters struct, provided via Fetch, XHR, or
+ * the iframe tag
+ * TODO(b/161890603): Trust Token: Remove the 'issuer' fields after Chrome 86
+ * hits stable.
+ * @record
+ * @see https://docs.google.com/document/d/1qUjtKgA7nMv9YGMhi0xWKEojkSITKzGLdIcZgoz6ZkI
+ */
+
+function TrustTokenAttributeType() {}
+
+/**
+ * Possible values: 'token-request', 'send-srr', 'srr-token-redemption'
+ * @type {string}
+ */
+TrustTokenAttributeType.prototype.type;
+
+/** @type {string|undefined} */
+TrustTokenAttributeType.prototype.issuer;
+
+/** @type {!Array<string>|undefined} */
+TrustTokenAttributeType.prototype.issuers;
+
+/**
+ * Possible values: 'none', 'refresh'
+ * @type {string|undefined}
+ */
+TrustTokenAttributeType.prototype.refreshPolicy;
+
+/**
+ * Possible values: 'omit', 'include', 'headers-only'
+ * @type {string|undefined}
+ */
+TrustTokenAttributeType.prototype.signRequestData;
+
+/** @type {boolean|undefined} */
+TrustTokenAttributeType.prototype.includeTimestampHeader;
+
+/** @type {!Array<string>|undefined} */
+TrustTokenAttributeType.prototype.additionalSignedHeaders;
+
+/** @type {string|undefined} */
+TrustTokenAttributeType.prototype.additionalSigningData;
+
+/**
+ * @type {?function(!TrustTokenAttributeType): void}
+ * @see https://docs.google.com/document/d/1qUjtKgA7nMv9YGMhi0xWKEojkSITKzGLdIcZgoz6ZkI.
+ */
+XMLHttpRequest.prototype.setTrustToken;
+
+/**
+ * @param {!string} issuer The trust token issuer, e.g.
+ *     https://adservice.google.com
+ * @return {!Promise<boolean>}
+ * @see https://docs.google.com/document/d/1TNnya6B8pyomDK2F1R9CL3dY10OAmqWlnCxsWyOBDVQ/edit
+ */
+Document.prototype.hasTrustToken = function(issuer) {};
+
+/** @type {undefined|!TrustTokenAttributeType} */
+RequestInit.prototype.trustToken;
+
+/**
+ * @type {undefined|!TrustTokenAttributeType}
+ * @see https://github.com/WICG/trust-token-api#extension-iframe-activation
+ */
+HTMLIFrameElement.prototype.trustToken;
diff --git a/javascript/externs/web/wicg_uach.js b/javascript/externs/web/wicg_uach.js
new file mode 100644
index 000000000000..54c1b22d9be1
--- /dev/null
+++ b/javascript/externs/web/wicg_uach.js
@@ -0,0 +1,85 @@
+/*
+ * Copyright 2008 The Closure Compiler Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview The current draft spec of User Agent Client Hint interface.
+ * @see https://wicg.github.io/ua-client-hints/#interface
+ * @externs
+ */
+
+/**
+ * @see https://wicg.github.io/ua-client-hints/#dictdef-navigatoruabrandversion
+ * @record
+ * @struct
+ */
+function NavigatorUABrandVersion() {}
+
+/** @type {string} */
+NavigatorUABrandVersion.prototype.brand;
+
+/** @type {string} */
+NavigatorUABrandVersion.prototype.version;
+
+
+/**
+ * @see https://wicg.github.io/ua-client-hints/#dictdef-uadatavalues
+ * @record
+ * @struct
+ */
+function UADataValues() {}
+
+/** @type {string} */
+UADataValues.prototype.platform;
+
+/** @type {string} */
+UADataValues.prototype.platformVersion;
+
+/** @type {string} */
+UADataValues.prototype.architecture;
+
+/** @type {string} */
+UADataValues.prototype.model;
+
+/** @type {string} */
+UADataValues.prototype.uaFullVersion;
+
+/**
+ * @see https://wicg.github.io/ua-client-hints/#navigatoruadata
+ * @record
+ * @struct
+ */
+function NavigatorUAData() {}
+
+/** @type {!Array<!NavigatorUABrandVersion>} */
+NavigatorUAData.prototype.brands;
+
+/** @type {boolean} */
+NavigatorUAData.prototype.mobile;
+
+/** @type {function(!Array<string>) : !Promise<!UADataValues>} */
+NavigatorUAData.prototype.getHighEntropyValues;
+
+/**
+ * @type {?NavigatorUAData}
+ * @see https://wicg.github.io/ua-client-hints/#interface
+ */
+Navigator.prototype.userAgentData;
+
+/**
+ * @type {?NavigatorUAData}
+ * @see https://wicg.github.io/ua-client-hints/#interface
+ */
+WorkerNavigator.prototype.userAgentData;

From cbc3dfa791a39641bd86099a9382005d57c53a51 Mon Sep 17 00:00:00 2001
From: Erik Krogh Kristensen <erik-krogh@github.com>
Date: Thu, 11 Mar 2021 19:14:49 +0100
Subject: [PATCH 6/6] update web externs

---
 javascript/externs/web/chrome.js              |  361 +--
 javascript/externs/web/fetchapi.js            |   30 +-
 javascript/externs/web/fileapi.js             |  799 +++---
 javascript/externs/web/flash.js               |   12 +-
 javascript/externs/web/gecko_dom.js           |  446 +---
 javascript/externs/web/gecko_event.js         |   31 +-
 javascript/externs/web/gecko_xml.js           |    4 +-
 javascript/externs/web/html5.js               | 2349 +++++++++++++----
 javascript/externs/web/ie_css.js              |    3 +
 javascript/externs/web/ie_dom.js              |  337 +--
 javascript/externs/web/ie_event.js            |    8 +-
 javascript/externs/web/mediasource.js         |   50 +-
 javascript/externs/web/streamsapi.js          |  190 +-
 javascript/externs/web/url.js                 |   60 +-
 javascript/externs/web/w3c_anim_timing.js     |    8 +-
 javascript/externs/web/w3c_batterystatus.js   |   16 +-
 javascript/externs/web/w3c_css.js             |  597 ++++-
 .../externs/web/w3c_device_sensor_event.js    |   23 +-
 javascript/externs/web/w3c_dom1.js            |  290 +-
 javascript/externs/web/w3c_dom2.js            |  394 ++-
 javascript/externs/web/w3c_dom3.js            |  352 +--
 javascript/externs/web/w3c_dom4.js            |  220 ++
 javascript/externs/web/w3c_event.js           |   97 +-
 javascript/externs/web/w3c_geolocation.js     |   42 +-
 javascript/externs/web/w3c_indexeddb.js       |  688 ++---
 .../externs/web/w3c_navigation_timing.js      |  237 +-
 javascript/externs/web/w3c_permissions.js     |   28 +-
 javascript/externs/web/w3c_pointer_events.js  |   33 +-
 javascript/externs/web/w3c_range.js           |  103 +-
 .../externs/web/w3c_requestidlecallback.js    |    6 +-
 javascript/externs/web/w3c_rtc.js             | 1014 +++++--
 javascript/externs/web/w3c_serviceworker.js   |  212 +-
 javascript/externs/web/w3c_webcrypto.js       |  430 ++-
 javascript/externs/web/w3c_xml.js             |  234 +-
 javascript/externs/web/webgl.js               | 1319 +++++----
 javascript/externs/web/webkit_dom.js          |  221 +-
 javascript/externs/web/webkit_event.js        |    8 +-
 .../externs/web/webkit_notifications.js       |   61 +-
 javascript/externs/web/webkit_usercontent.js  |    3 +-
 javascript/externs/web/webstorage.js          |   47 +-
 javascript/externs/web/whatwg_encoding.js     |    9 +-
 javascript/externs/web/window.js              |  151 +-
 42 files changed, 7264 insertions(+), 4259 deletions(-)

diff --git a/javascript/externs/web/chrome.js b/javascript/externs/web/chrome.js
index d77b42e620c2..b80a97a6a3a5 100644
--- a/javascript/externs/web/chrome.js
+++ b/javascript/externs/web/chrome.js
@@ -65,246 +65,284 @@ Port.prototype.disconnect = function() {};
 
 
 /**
- * @see https://developer.chrome.com/extensions/events.html
- * @constructor
- * TODO(tbreisacher): Update *Listener methods to take {function()}
- * instead of {!Function}. See discussion at go/ChromeEvent-TODO
+ * Base event type without listener methods.
+ *
+ * This interface exists for event interfaces whose addListeners() method takes
+ * more than one parameter. Those interfaces must inherit from this one, so they
+ * can supply their own custom listener method declarations.
+ *
+ * Event interfaces whose addListeners() method takes just one parameter should
+ * inherit from ChromeBaseEvent instead. It extends this interface.
+ *
+ * @see https://developer.chrome.com/extensions/events
+ * @interface
  */
-function ChromeEvent() {}
+function ChromeBaseEventNoListeners() {}
 
 
 /**
- * @param {!Function} callback
- * @return {undefined}
+ * @param {!Array<!Rule>} rules
+ * @param {function(!Array<!Rule>): void=} callback
+ * @see https://developer.chrome.com/extensions/events#method-Event-addRules
  */
-ChromeEvent.prototype.addListener = function(callback) {};
+ChromeBaseEventNoListeners.prototype.addRules = function(rules, callback) {};
 
 
 /**
- * @param {!Function} callback
- * @return {undefined}
+ * Returns currently registered rules.
+ *
+ * NOTE: The API allows the first argument to be omitted.
+ *     That cannot be correctly represented here, so we end up incorrectly
+ *     allowing 2 callback arguments.
+ * @param {!Array<string>|function(!Array<!Rule>): void} ruleIdentifiersOrCb
+ * @param {function(!Array<!Rule>): void=} callback
+ * @see https://developer.chrome.com/extensions/events#method-Event-getRules
  */
-ChromeEvent.prototype.removeListener = function(callback) {};
+ChromeBaseEventNoListeners.prototype.getRules =
+    function(ruleIdentifiersOrCb, callback) {};
 
 
 /**
- * @param {!Function} callback
- * @return {boolean}
+ * Removes currently registered rules.
+ *
+ * NOTE: The API allows the either or both arguments to be omitted.
+ *     That cannot be correctly represented here, so we end up incorrectly
+ *     allowing 2 callback arguments.
+ * @param {(!Array<string>|function(): void)=} ruleIdentifiersOrCb
+ * @param {function(): void=} callback
+ * @see https://developer.chrome.com/extensions/events#method-Event-removeRules
  */
-ChromeEvent.prototype.hasListener = function(callback) {};
+ChromeBaseEventNoListeners.prototype.removeRules =
+    function(ruleIdentifiersOrCb, callback) {};
 
 
-/** @return {boolean} */
-ChromeEvent.prototype.hasListeners = function() {};
+/**
+ * @see https://developer.chrome.com/extensions/events#type-Rule
+ * @record
+ */
+function Rule() {}
 
-// TODO(tbreisacher): Add the addRules, getRules, and removeRules methods?
 
+/** @type {string|undefined} */
+Rule.prototype.id;
 
 
-/**
- * Event whose listeners take a string parameter.
- * @constructor
- */
-function ChromeStringEvent() {}
+/** @type {!Array<string>|undefined} */
+Rule.prototype.tags;
 
 
-/**
- * @param {function(string): void} callback
- * @return {undefined}
- */
-ChromeStringEvent.prototype.addListener = function(callback) {};
+/** @type {!Array<*>} */
+Rule.prototype.conditions;
 
 
-/**
- * @param {function(string): void} callback
- * @return {undefined}
- */
-ChromeStringEvent.prototype.removeListener = function(callback) {};
+/** @type {!Array<*>} */
+Rule.prototype.actions;
+
+
+/** @type {number|undefined} */
+Rule.prototype.priority;
 
 
 /**
- * @param {function(string): void} callback
- * @return {boolean}
+ * @see https://developer.chrome.com/extensions/events#type-UrlFilter
+ * @record
  */
-ChromeStringEvent.prototype.hasListener = function(callback) {};
+function UrlFilter() {}
 
 
-/** @return {boolean} */
-ChromeStringEvent.prototype.hasListeners = function() {};
+/** @type {string|undefined} */
+UrlFilter.prototype.hostContains;
 
 
+/** @type {string|undefined} */
+UrlFilter.prototype.hostEquals;
 
-/**
- * Event whose listeners take a boolean parameter.
- * @constructor
- */
 
-function ChromeBooleanEvent() {}
+/** @type {string|undefined} */
+UrlFilter.prototype.hostPrefix;
 
 
-/**
- * @param {function(boolean): void} callback
- * @return {undefined}
- */
-ChromeBooleanEvent.prototype.addListener = function(callback) {};
+/** @type {string|undefined} */
+UrlFilter.prototype.hostSuffix;
 
 
-/**
- * @param {function(boolean): void} callback
- * @return {undefined}
- */
-ChromeBooleanEvent.prototype.removeListener = function(callback) {};
+/** @type {string|undefined} */
+UrlFilter.prototype.pathContains;
 
 
-/**
- * @param {function(boolean): void} callback
- * @return {boolean}
- */
-ChromeBooleanEvent.prototype.hasListener = function(callback) {};
+/** @type {string|undefined} */
+UrlFilter.prototype.pathEquals;
 
 
-/**
- * @return {boolean}
- */
-ChromeBooleanEvent.prototype.hasListeners = function() {};
+/** @type {string|undefined} */
+UrlFilter.prototype.pathPrefix;
 
 
+/** @type {string|undefined} */
+UrlFilter.prototype.pathSuffix;
 
-/**
- * Event whose listeners take a number parameter.
- * @constructor
- */
 
-function ChromeNumberEvent() {}
+/** @type {string|undefined} */
+UrlFilter.prototype.queryContains;
 
 
-/**
- * @param {function(number): void} callback
- * @return {undefined}
- */
-ChromeNumberEvent.prototype.addListener = function(callback) {};
+/** @type {string|undefined} */
+UrlFilter.prototype.queryEquals;
 
 
-/**
- * @param {function(number): void} callback
- * @return {undefined}
- */
-ChromeNumberEvent.prototype.removeListener = function(callback) {};
+/** @type {string|undefined} */
+UrlFilter.prototype.queryPrefix;
 
 
-/**
- * @param {function(number): void} callback
- * @return {boolean}
- */
-ChromeNumberEvent.prototype.hasListener = function(callback) {};
+/** @type {string|undefined} */
+UrlFilter.prototype.querySuffix;
 
 
-/**
- * @return {boolean}
- */
-ChromeNumberEvent.prototype.hasListeners = function() {};
+/** @type {string|undefined} */
+UrlFilter.prototype.urlContains;
 
 
+/** @type {string|undefined} */
+UrlFilter.prototype.urlEquals;
+
+
+/** @type {string|undefined} */
+UrlFilter.prototype.urlMatches;
+
+
+/** @type {string|undefined} */
+UrlFilter.prototype.originAndPathMatches;
+
+
+/** @type {string|undefined} */
+UrlFilter.prototype.urlPrefix;
+
+
+/** @type {string|undefined} */
+UrlFilter.prototype.urlSuffix;
+
+
+/** @type {!Array<string>|undefined} */
+UrlFilter.prototype.schemes;
+
+
+/** @type {!Array<(number|!Array<number>)>|undefined} */
+UrlFilter.prototype.ports;
+
 
 /**
- * Event whose listeners take an Object parameter.
- * @constructor
+ * Base event type from which all others inherit.
+ *
+ * LISTENER must be a function type that returns void.
+ *
+ * @see https://developer.chrome.com/extensions/events
+ * @interface
+ * @extends {ChromeBaseEventNoListeners}
+ * @template LISTENER
  */
-function ChromeObjectEvent() {}
+function ChromeBaseEvent() {}
 
 
 /**
- * @param {function(!Object): void} callback Callback.
+ * @param {LISTENER} callback
  * @return {undefined}
+ * @see https://developer.chrome.com/extensions/events#method-Event-addListener
  */
-ChromeObjectEvent.prototype.addListener = function(callback) {};
+ChromeBaseEvent.prototype.addListener = function(callback) {};
 
 
 /**
- * @param {function(!Object): void} callback Callback.
+ * @param {LISTENER} callback
  * @return {undefined}
+ * @see https://developer.chrome.com/extensions/events#method-Event-removeListener
  */
-ChromeObjectEvent.prototype.removeListener = function(callback) {};
+ChromeBaseEvent.prototype.removeListener = function(callback) {};
 
 
 /**
- * @param {function(!Object): void} callback Callback.
+ * @param {LISTENER} callback
  * @return {boolean}
+ * @see https://developer.chrome.com/extensions/events#method-Event-hasListener
  */
-ChromeObjectEvent.prototype.hasListener = function(callback) {};
+ChromeBaseEvent.prototype.hasListener = function(callback) {};
 
 
 /**
  * @return {boolean}
+ * @see https://developer.chrome.com/extensions/events#method-Event-hasListeners
  */
-ChromeObjectEvent.prototype.hasListeners = function() {};
-
+ChromeBaseEvent.prototype.hasListeners = function() {};
 
 
 /**
- * Event whose listeners take a string array parameter.
- * @constructor
+ * Event whose listeners take unspecified parameters.
+ *
+ * TODO(bradfordcsmith): Definitions using this type are failing to provide
+ *     information about the parameters that will actually be supplied to the
+ *     listener and should be updated to use a more specific event type.
+ * @see https://developer.chrome.com/extensions/events
+ * @interface
+ * @extends {ChromeBaseEvent<!Function>}
  */
-function ChromeStringArrayEvent() {}
+function ChromeEvent() {}
 
 
 /**
- * @param {function(!Array<string>): void} callback
- * @return {undefined}
+ * Event whose listeners take no parameters.
+ *
+ * @see https://developer.chrome.com/extensions/events
+ * @interface
+ * @extends {ChromeBaseEvent<function()>}
  */
-ChromeStringArrayEvent.prototype.addListener = function(callback) {};
+function ChromeVoidEvent() {}
 
 
 /**
- * @param {function(!Array<string>): void} callback
- * @return {undefined}
+ * Event whose listeners take a string parameter.
+ * @interface
+ * @extends {ChromeBaseEvent<function(string)>}
  */
-ChromeStringArrayEvent.prototype.removeListener = function(callback) {};
+function ChromeStringEvent() {}
 
 
 /**
- * @param {function(!Array<string>): void} callback
- * @return {boolean}
+ * Event whose listeners take a boolean parameter.
+ * @interface
+ * @extends {ChromeBaseEvent<function(boolean)>}
  */
-ChromeStringArrayEvent.prototype.hasListener = function(callback) {};
-
-
-/** @return {boolean} */
-ChromeStringArrayEvent.prototype.hasListeners = function() {};
-
+function ChromeBooleanEvent() {}
 
 
 /**
- * Event whose listeners take two strings as parameters.
- * @constructor
+ * Event whose listeners take a number parameter.
+ * @interface
+ * @extends {ChromeBaseEvent<function(number)>}
  */
-function ChromeStringStringEvent() {}
+function ChromeNumberEvent() {}
 
 
 /**
- * @param {function(string, string): void} callback
- * @return {undefined}
+ * Event whose listeners take an Object parameter.
+ * @interface
+ * @extends {ChromeBaseEvent<function(!Object)>}
  */
-ChromeStringStringEvent.prototype.addListener = function(callback) {};
+function ChromeObjectEvent() {}
 
 
 /**
- * @param {function(string, string): void} callback
- * @return {undefined}
+ * Event whose listeners take a string array parameter.
+ * @interface
+ * @extends {ChromeBaseEvent<function(!Array<string>)>}
  */
-ChromeStringStringEvent.prototype.removeListener = function(callback) {};
+function ChromeStringArrayEvent() {}
 
 
 /**
- * @param {function(string, string): void} callback
- * @return {boolean}
+ * Event whose listeners take two strings as parameters.
+ * @interface
+ * @extends {ChromeBaseEvent<function(string, string)>}
  */
-ChromeStringStringEvent.prototype.hasListener = function(callback) {};
-
-
-/** @return {boolean} */
-ChromeStringStringEvent.prototype.hasListeners = function() {};
-
+function ChromeStringStringEvent() {}
 
 
 /**
@@ -330,10 +368,18 @@ MessageSender.prototype.id;
 MessageSender.prototype.url;
 
 
+/** @type {string|undefined} */
+MessageSender.prototype.nativeApplication;
+
+
 /** @type {string|undefined} */
 MessageSender.prototype.tlsChannelId;
 
 
+/** @type {string|undefined} */
+MessageSender.prototype.origin;
+
+
 /**
  * @enum {string}
  * @see https://developer.chrome.com/extensions/tabs#type-MutedInfoReason
@@ -424,6 +470,10 @@ Tab.prototype.mutedInfo;
 Tab.prototype.url;
 
 
+/** @type {string|undefined} */
+Tab.prototype.pendingUrl;
+
+
 // TODO: Make this field optional once dependent projects have been updated.
 /** @type {string} */
 Tab.prototype.title;
@@ -503,12 +553,8 @@ chrome.webstore.onDownloadProgress;
 chrome.runtime = {};
 
 
-/** @type {!Object|undefined} */
-chrome.runtime.lastError = {};
-
-
-/** @type {string|undefined} */
-chrome.runtime.lastError.message;
+/** @type {{message:(string|undefined)}|undefined} */
+chrome.runtime.lastError;
 
 
 /**
@@ -618,49 +664,6 @@ ChromeLoadTimes.prototype.wasAlternateProtocolAvailable;
 ChromeLoadTimes.prototype.connectionInfo;
 
 
-/**
- * Returns an object containing timing information.
- * @return {!ChromeCsiInfo}
- */
-chrome.csi = function() {};
-
-
-
-/**
- * The data object given by chrome.csi().
- * @constructor
- */
-function ChromeCsiInfo() {}
-
-
-/**
- * Same as chrome.loadTimes().requestTime, if defined.
- * Otherwise, gives the same value as chrome.loadTimes().startLoadTime.
- * In milliseconds, truncated.
- * @type {number}
- */
-ChromeCsiInfo.prototype.startE;
-
-
-/**
- * Same as chrome.loadTimes().finishDocumentLoadTime but in milliseconds and
- * truncated.
- * @type {number}
- */
-ChromeCsiInfo.prototype.onloadT;
-
-
-/**
- * The time since startE in milliseconds.
- * @type {number}
- */
-ChromeCsiInfo.prototype.pageT;
-
-
-/** @type {number} */
-ChromeCsiInfo.prototype.tran;
-
-
 /**
  * @param {string|!ArrayBuffer|!Object} message
  * @see https://developers.google.com/native-client/devguide/tutorial
diff --git a/javascript/externs/web/fetchapi.js b/javascript/externs/web/fetchapi.js
index 6c4f93a62b10..79e42ae8de82 100644
--- a/javascript/externs/web/fetchapi.js
+++ b/javascript/externs/web/fetchapi.js
@@ -37,8 +37,8 @@ var ReferrerPolicy;
 
 
 /**
- * @typedef {!Headers|!Array<!Array<string>>|!IObject<string,string>}
- * @see https://fetch.spec.whatwg.org/#headersinit
+ * @typedef {!Headers|!Array<!Array<string>>|!Object<string,string>}
+ * @see https://fetch.spec.whatwg.org/#typedefdef-headersinit
  */
 var HeadersInit;
 
@@ -64,7 +64,7 @@ Headers.prototype.append = function(name, value) {};
  */
 Headers.prototype.delete = function(name) {};
 
-/** @return {!Iterator<!Array<string>>} */
+/** @return {!IteratorIterable<!Array<string>>} */
 Headers.prototype.entries = function() {};
 
 /**
@@ -85,7 +85,7 @@ Headers.prototype.getAll = function(name) {};
  */
 Headers.prototype.has = function(name) {};
 
-/** @return {!Iterator<string>} */
+/** @return {!IteratorIterable<string>} */
 Headers.prototype.keys = function() {};
 
 /**
@@ -103,7 +103,8 @@ Headers.prototype[Symbol.iterator] = function() {};
 
 
 /**
- * @typedef {!Blob|!BufferSource|!FormData|string}
+ * @typedef {
+ *     !Blob|!BufferSource|!FormData|!URLSearchParams|!ReadableStream|string}
  * @see https://fetch.spec.whatwg.org/#bodyinit
  */
 var BodyInit;
@@ -208,6 +209,12 @@ Request.prototype.redirect;
 /** @type {string} */
 Request.prototype.integrity;
 
+/** @type {boolean} */
+Request.prototype.isHistoryNavigation;
+
+/** @type {(undefined|boolean)} */
+Request.prototype.keepalive;
+
 /** @return {!Request} */
 Request.prototype.clone = function() {};
 
@@ -248,6 +255,12 @@ RequestInit.prototype.redirect;
 /** @type {(undefined|string)} */
 RequestInit.prototype.integrity;
 
+/** @type {(undefined|!AbortSignal)} */
+RequestInit.prototype.signal;
+
+/** @type {(undefined|boolean)} */
+RequestInit.prototype.keepalive;
+
 /** @type {(undefined|null)} */
 RequestInit.prototype.window;
 
@@ -418,3 +431,10 @@ Window.prototype.fetch = function(input, opt_init) {};
  * @see https://fetch.spec.whatwg.org/#fetch-method
  */
 WorkerGlobalScope.prototype.fetch = function(input, opt_init) {};
+
+/**
+ * if WorkerOptions.type = 'module', it specifies how `scriptURL` is fetched.
+ * WorkerOptions is defined in html5.js.
+ * @type {!RequestCredentials|undefined}
+ */
+WorkerOptions.prototype.credentials;
diff --git a/javascript/externs/web/fileapi.js b/javascript/externs/web/fileapi.js
index 21095b9eeaf8..02861fd9810c 100644
--- a/javascript/externs/web/fileapi.js
+++ b/javascript/externs/web/fileapi.js
@@ -1,5 +1,5 @@
 /*
- * Copyright 2010 The Closure Compiler Authors
+ * Copyright 2019 The Closure Compiler Authors
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -13,70 +13,34 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-/**
- * @fileoverview Definitions for objects in the File API, File Writer API, and
- * File System API. Details of the API are at:
- * http://www.w3.org/TR/FileAPI/
- * http://www.w3.org/TR/file-writer-api/
- * http://www.w3.org/TR/file-system-api/
- *
- * @externs
- * @author dbk@google.com (David Barrett-Kahn)
- */
-
 
 /**
- * @see http://dev.w3.org/2006/webapi/FileAPI/#dfn-Blob
- * @param {Array<ArrayBuffer|ArrayBufferView|Blob|string>=} opt_blobParts
- * @param {Object=} opt_options
- * @constructor
- * @nosideeffects
- */
-function Blob(opt_blobParts, opt_options) {}
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-size
- * @type {number}
- */
-Blob.prototype.size;
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-type
- * @type {string}
- */
-Blob.prototype.type;
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-slice
- * @param {number=} start
- * @param {number=} length
- * @param {string=} opt_contentType
- * @return {!Blob}
- * @nosideeffects
+ * @fileoverview Definitions for file api implemented in
+ *     various browsers but not part of https://www.w3.org/TR/FileAPI.
+ * @externs
  */
-Blob.prototype.slice = function(start, length, opt_contentType) {};
 
 /**
  * This replaces Blob.slice in Chrome since WebKit revision 84005.
  * @see http://lists.w3.org/Archives/Public/public-webapps/2011AprJun/0222.html
  * @param {number=} start
  * @param {number=} end
- * @param {string=} opt_contentType
+ * @param {string=} contentType
  * @return {!Blob}
  * @nosideeffects
  */
-Blob.prototype.webkitSlice = function(start, end, opt_contentType) {};
+Blob.prototype.webkitSlice = function(start, end, contentType) {};
 
 /**
  * This replaces Blob.slice in Firefox.
  * @see http://lists.w3.org/Archives/Public/public-webapps/2011AprJun/0222.html
  * @param {number=} start
  * @param {number=} end
- * @param {string=} opt_contentType
+ * @param {string=} contentType
  * @return {!Blob}
  * @nosideeffects
  */
-Blob.prototype.mozSlice = function(start, end, opt_contentType) {};
+Blob.prototype.mozSlice = function(start, end, contentType) {};
 
 /**
  * @see http://www.w3.org/TR/file-writer-api/#the-blobbuilder-interface
@@ -125,7 +89,6 @@ WebKitBlobBuilder.prototype.append = function(data, endings) {};
  */
 WebKitBlobBuilder.prototype.getBlob = function(contentType) {};
 
-
 /**
  * @record
  * @see https://dev.w3.org/2009/dap/file-system/file-dir-sys.html#the-flags-dictionary
@@ -138,7 +101,6 @@ FileSystemFlags.prototype.create;
 /** @type {(undefined|boolean)} */
 FileSystemFlags.prototype.exclusive;
 
-
 /**
  * @see http://www.w3.org/TR/file-system-api/#the-directoryentry-interface
  * @constructor
@@ -160,8 +122,8 @@ DirectoryEntry.prototype.createReader = function() {};
  * @param {function(!FileError)=} errorCallback
  * @return {undefined}
  */
-DirectoryEntry.prototype.getFile = function(path, options, successCallback,
-    errorCallback) {};
+DirectoryEntry.prototype.getFile = function(
+    path, options, successCallback, errorCallback) {};
 
 /**
  * @see http://www.w3.org/TR/file-system-api/#widl-DirectoryEntry-getDirectory
@@ -171,8 +133,8 @@ DirectoryEntry.prototype.getFile = function(path, options, successCallback,
  * @param {function(!FileError)=} errorCallback
  * @return {undefined}
  */
-DirectoryEntry.prototype.getDirectory = function(path, options, successCallback,
-    errorCallback) {};
+DirectoryEntry.prototype.getDirectory = function(
+    path, options, successCallback, errorCallback) {};
 
 /**
  * @see http://www.w3.org/TR/file-system-api/#widl-DirectoryEntry-removeRecursively
@@ -180,8 +142,8 @@ DirectoryEntry.prototype.getDirectory = function(path, options, successCallback,
  * @param {function(!FileError)=} errorCallback
  * @return {undefined}
  */
-DirectoryEntry.prototype.removeRecursively = function(successCallback,
-    errorCallback) {};
+DirectoryEntry.prototype.removeRecursively = function(
+    successCallback, errorCallback) {};
 
 /**
  * @see http://www.w3.org/TR/file-system-api/#the-directoryreader-interface
@@ -195,8 +157,8 @@ function DirectoryReader() {};
  * @param {function(!FileError)=} errorCallback
  * @return {undefined}
  */
-DirectoryReader.prototype.readEntries = function(successCallback,
-    errorCallback) {};
+DirectoryReader.prototype.readEntries = function(
+    successCallback, errorCallback) {};
 
 /**
  * @see http://www.w3.org/TR/file-system-api/#the-entry-interface
@@ -242,8 +204,8 @@ Entry.prototype.filesystem;
  * @param {function(!FileError)=} errorCallback
  * @return {undefined}
  */
-Entry.prototype.moveTo = function(parent, newName, successCallback,
-    errorCallback) {};
+Entry.prototype.moveTo = function(
+    parent, newName, successCallback, errorCallback) {};
 
 /**
  * @see http://www.w3.org/TR/file-system-api/#widl-Entry-copyTo
@@ -253,8 +215,8 @@ Entry.prototype.moveTo = function(parent, newName, successCallback,
  * @param {function(!FileError)=} errorCallback
  * @return {undefined}
  */
-Entry.prototype.copyTo = function(parent, newName, successCallback,
-    errorCallback) {};
+Entry.prototype.copyTo = function(
+    parent, newName, successCallback, errorCallback) {};
 
 /**
  * @see http://www.w3.org/TR/file-system-api/#widl-Entry-toURL
@@ -288,47 +250,18 @@ Entry.prototype.getMetadata = function(successCallback, errorCallback) {};
 Entry.prototype.getParent = function(successCallback, errorCallback) {};
 
 /**
- * @see http://www.w3.org/TR/FileAPI/#dfn-file
- * @param {!Array<string|!Blob|!ArrayBuffer>=} opt_contents
- * @param {string=} opt_name
- * @param {{type: (string|undefined), lastModified: (number|undefined)}=}
- *     opt_properties
- * @constructor
- * @extends {Blob}
- */
-function File(opt_contents, opt_name, opt_properties) {}
-
-/**
- * Chrome uses this instead of name.
- * @deprecated Use name instead.
- * @type {string}
- */
-File.prototype.fileName;
-
-/**
- * Chrome uses this instead of size.
- * @deprecated Use size instead.
- * @type {string}
+ * @return {?Entry} The Entry corresponding to this item, or null. Note that
+ * despite its name,this method only works in Chrome, and will eventually
+ * be renamed to {@code getAsEntry}.
+ * @nosideeffects
  */
-File.prototype.fileSize;
+DataTransferItem.prototype.webkitGetAsEntry = function() {};
 
 /**
- * @see http://www.w3.org/TR/FileAPI/#dfn-name
+ * @see https://wicg.github.io/entries-api/#dom-file-webkitrelativepath
  * @type {string}
  */
-File.prototype.name;
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-lastModifiedDate
- * @type {Date}
- */
-File.prototype.lastModifiedDate;
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-lastModified
- * @type {number}
- */
-File.prototype.lastModified;
+File.prototype.webkitRelativePath;
 
 /**
  * @see http://www.w3.org/TR/file-system-api/#the-fileentry-interface
@@ -362,111 +295,111 @@ function FileError() {}
 
 /**
  * @see http://www.w3.org/TR/FileAPI/#dfn-NOT_FOUND_ERR
- * @type {number}
+ * @const {number}
  */
-FileError.prototype.NOT_FOUND_ERR = 1;
+FileError.prototype.NOT_FOUND_ERR;
 
-/** @type {number} */
-FileError.NOT_FOUND_ERR = 1;
+/** @const {number} */
+FileError.NOT_FOUND_ERR;
 
 /**
  * @see http://www.w3.org/TR/FileAPI/#dfn-SECURITY_ERR
- * @type {number}
+ * @const {number}
  */
-FileError.prototype.SECURITY_ERR = 2;
+FileError.prototype.SECURITY_ERR;
 
-/** @type {number} */
-FileError.SECURITY_ERR = 2;
+/** @const {number} */
+FileError.SECURITY_ERR;
 
 /**
  * @see http://www.w3.org/TR/FileAPI/#dfn-ABORT_ERR
- * @type {number}
+ * @const {number}
  */
-FileError.prototype.ABORT_ERR = 3;
+FileError.prototype.ABORT_ERR;
 
-/** @type {number} */
-FileError.ABORT_ERR = 3;
+/** @const {number} */
+FileError.ABORT_ERR;
 
 /**
  * @see http://www.w3.org/TR/FileAPI/#dfn-NOT_READABLE_ERR
- * @type {number}
+ * @const {number}
  */
-FileError.prototype.NOT_READABLE_ERR = 4;
+FileError.prototype.NOT_READABLE_ERR;
 
-/** @type {number} */
-FileError.NOT_READABLE_ERR = 4;
+/** @const {number} */
+FileError.NOT_READABLE_ERR;
 
 /**
  * @see http://www.w3.org/TR/FileAPI/#dfn-ENCODING_ERR
- * @type {number}
+ * @const {number}
  */
-FileError.prototype.ENCODING_ERR = 5;
+FileError.prototype.ENCODING_ERR;
 
-/** @type {number} */
-FileError.ENCODING_ERR = 5;
+/** @const {number} */
+FileError.ENCODING_ERR;
 
 /**
  * @see http://www.w3.org/TR/file-writer-api/#widl-FileError-NO_MODIFICATION_ALLOWED_ERR
- * @type {number}
+ * @const {number}
  */
-FileError.prototype.NO_MODIFICATION_ALLOWED_ERR = 6;
+FileError.prototype.NO_MODIFICATION_ALLOWED_ERR;
 
-/** @type {number} */
-FileError.NO_MODIFICATION_ALLOWED_ERR = 6;
+/** @const {number} */
+FileError.NO_MODIFICATION_ALLOWED_ERR;
 
 /**
  * @see http://www.w3.org/TR/file-writer-api/#widl-FileException-INVALID_STATE_ERR
- * @type {number}
+ * @const {number}
  */
-FileError.prototype.INVALID_STATE_ERR = 7;
+FileError.prototype.INVALID_STATE_ERR;
 
-/** @type {number} */
-FileError.INVALID_STATE_ERR = 7;
+/** @const {number} */
+FileError.INVALID_STATE_ERR;
 
 /**
  * @see http://www.w3.org/TR/file-writer-api/#widl-FileException-SYNTAX_ERR
- * @type {number}
+ * @const {number}
  */
-FileError.prototype.SYNTAX_ERR = 8;
+FileError.prototype.SYNTAX_ERR;
 
-/** @type {number} */
-FileError.SYNTAX_ERR = 8;
+/** @const {number} */
+FileError.SYNTAX_ERR;
 
 /**
  * @see http://www.w3.org/TR/file-system-api/#widl-FileError-INVALID_MODIFICATION_ERR
- * @type {number}
+ * @const {number}
  */
-FileError.prototype.INVALID_MODIFICATION_ERR = 9;
+FileError.prototype.INVALID_MODIFICATION_ERR;
 
-/** @type {number} */
-FileError.INVALID_MODIFICATION_ERR = 9;
+/** @const {number} */
+FileError.INVALID_MODIFICATION_ERR;
 
 /**
  * @see http://www.w3.org/TR/file-system-api/#widl-FileError-QUOTA_EXCEEDED_ERR
- * @type {number}
+ * @const {number}
  */
-FileError.prototype.QUOTA_EXCEEDED_ERR = 10;
+FileError.prototype.QUOTA_EXCEEDED_ERR;
 
-/** @type {number} */
-FileError.QUOTA_EXCEEDED_ERR = 10;
+/** @const {number} */
+FileError.QUOTA_EXCEEDED_ERR;
 
 /**
  * @see http://www.w3.org/TR/file-system-api/#widl-FileException-TYPE_MISMATCH_ERR
- * @type {number}
+ * @const {number}
  */
-FileError.prototype.TYPE_MISMATCH_ERR = 11;
+FileError.prototype.TYPE_MISMATCH_ERR;
 
-/** @type {number} */
-FileError.TYPE_MISMATCH_ERR = 11;
+/** @const {number} */
+FileError.TYPE_MISMATCH_ERR;
 
 /**
  * @see http://www.w3.org/TR/file-system-api/#widl-FileException-PATH_EXISTS_ERR
- * @type {number}
+ * @const {number}
  */
-FileError.prototype.PATH_EXISTS_ERR = 12;
+FileError.prototype.PATH_EXISTS_ERR;
 
-/** @type {number} */
-FileError.PATH_EXISTS_ERR = 12;
+/** @const {number} */
+FileError.PATH_EXISTS_ERR;
 
 /**
  * @see http://www.w3.org/TR/FileAPI/#dfn-code-exception
@@ -476,151 +409,6 @@ FileError.PATH_EXISTS_ERR = 12;
  */
 FileError.prototype.code;
 
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-filereader
- * @constructor
- * @implements {EventTarget}
- */
-function FileReader() {}
-
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-FileReader.prototype.addEventListener = function(type, listener, opt_useCapture)
-    {};
-
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-FileReader.prototype.removeEventListener = function(type, listener,
-    opt_useCapture) {};
-
-/**
- * @override
- * @return {boolean}
- */
-FileReader.prototype.dispatchEvent = function(evt) {};
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-readAsArrayBuffer
- * @param {!Blob} blob
- * @return {undefined}
- */
-FileReader.prototype.readAsArrayBuffer = function(blob) {};
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-readAsBinaryStringAsync
- * @param {!Blob} blob
- * @return {undefined}
- */
-FileReader.prototype.readAsBinaryString = function(blob) {};
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-readAsText
- * @param {!Blob} blob
- * @param {string=} encoding
- * @return {undefined}
- */
-FileReader.prototype.readAsText = function(blob, encoding) {};
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-readAsDataURL
- * @param {!Blob} blob
- * @return {undefined}
- */
-FileReader.prototype.readAsDataURL = function(blob) {};
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-abort
- * @return {undefined}
- */
-FileReader.prototype.abort = function() {};
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-empty
- * @type {number}
- */
-FileReader.prototype.EMPTY = 0;
-
-/** @type {number} */
-FileReader.EMPTY = 0;
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-loading
- * @type {number}
- */
-FileReader.prototype.LOADING = 1;
-
-/** @type {number} */
-FileReader.LOADING = 1;
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-done
- * @type {number}
- */
-FileReader.prototype.DONE = 2;
-
-/** @type {number} */
-FileReader.DONE = 2;
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-readystate
- * @type {number}
- */
-FileReader.prototype.readyState;
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-result
- * @type {string|Blob|ArrayBuffer}
- */
-FileReader.prototype.result;
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-error
- * @type {FileError}
- */
-FileReader.prototype.error;
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-onloadstart
- * @type {?function(!ProgressEvent)}
- */
-FileReader.prototype.onloadstart;
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-onprogress
- * @type {?function(!ProgressEvent)}
- */
-FileReader.prototype.onprogress;
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-onload
- * @type {?function(!ProgressEvent)}
- */
-FileReader.prototype.onload;
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-onabort
- * @type {?function(!ProgressEvent)}
- */
-FileReader.prototype.onabort;
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-onerror
- * @type {?function(!ProgressEvent)}
- */
-FileReader.prototype.onerror;
-
-/**
- * @see http://www.w3.org/TR/FileAPI/#dfn-onloadend
- * @type {?function(!ProgressEvent)}
- */
-FileReader.prototype.onloadend;
-
 /**
  * @see http://www.w3.org/TR/file-writer-api/#idl-def-FileSaver
  * @constructor
@@ -635,21 +423,21 @@ FileSaver.prototype.abort = function() {};
 
 /**
  * @see http://www.w3.org/TR/file-writer-api/#widl-FileSaver-INIT
- * @type {number}
+ * @const {number}
  */
-FileSaver.prototype.INIT = 0;
+FileSaver.prototype.INIT;
 
 /**
  * @see http://www.w3.org/TR/file-writer-api/#widl-FileSaver-WRITING
- * @type {number}
+ * @const {number}
  */
-FileSaver.prototype.WRITING = 1;
+FileSaver.prototype.WRITING;
 
 /**
  * @see http://www.w3.org/TR/file-writer-api/#widl-FileSaver-DONE
- * @type {number}
+ * @const {number}
  */
-FileSaver.prototype.DONE = 2;
+FileSaver.prototype.DONE;
 
 /**
  * @see http://www.w3.org/TR/file-writer-api/#widl-FileSaver-readyState
@@ -665,37 +453,37 @@ FileSaver.prototype.error;
 
 /**
  * @see http://www.w3.org/TR/file-writer-api/#widl-FileSaver-onwritestart
- * @type {?function(!ProgressEvent)}
+ * @type {?function(!ProgressEvent<!FileSaver>)}
  */
 FileSaver.prototype.onwritestart;
 
 /**
  * @see http://www.w3.org/TR/file-writer-api/#widl-FileSaver-onprogress
- * @type {?function(!ProgressEvent)}
+ * @type {?function(!ProgressEvent<!FileSaver>)}
  */
 FileSaver.prototype.onprogress;
 
 /**
  * @see http://www.w3.org/TR/file-writer-api/#widl-FileSaver-onwrite
- * @type {?function(!ProgressEvent)}
+ * @type {?function(!ProgressEvent<!FileSaver>)}
  */
 FileSaver.prototype.onwrite;
 
 /**
  * @see http://www.w3.org/TR/file-writer-api/#widl-FileSaver-onabort
- * @type {?function(!ProgressEvent)}
+ * @type {?function(!ProgressEvent<!FileSaver>)}
  */
 FileSaver.prototype.onabort;
 
 /**
  * @see http://www.w3.org/TR/file-writer-api/#widl-FileSaver-onerror
- * @type {?function(!ProgressEvent)}
+ * @type {?function(!ProgressEvent<!FileSaver>)}
  */
 FileSaver.prototype.onerror;
 
 /**
  * @see http://www.w3.org/TR/file-writer-api/#widl-FileSaver-onwriteend
- * @type {?function(!ProgressEvent)}
+ * @type {?function(!ProgressEvent<!FileSaver>)}
  */
 FileSaver.prototype.onwriteend;
 
@@ -785,15 +573,15 @@ Metadata.prototype.size;
 
 /**
  * @see http://www.w3.org/TR/file-system-api/#widl-LocalFileSystem-TEMPORARY
- * @type {number}
-*/
-Window.prototype.TEMPORARY = 0;
+ * @const {number}
+ */
+Window.prototype.TEMPORARY;
 
 /**
  * @see http://www.w3.org/TR/file-system-api/#widl-LocalFileSystem-PERSISTENT
- * @type {number}
-*/
-Window.prototype.PERSISTENT = 1;
+ * @const {number}
+ */
+Window.prototype.PERSISTENT;
 
 /**
  * @see http://www.w3.org/TR/file-system-api/#widl-LocalFileSystem-requestFileSystem
@@ -813,8 +601,8 @@ function requestFileSystem(type, size, successCallback, errorCallback) {}
  * @param {function(!FileError)=} errorCallback
  * @return {undefined}
  */
-Window.prototype.requestFileSystem = function(type, size, successCallback,
-    errorCallback) {};
+Window.prototype.requestFileSystem = function(
+    type, size, successCallback, errorCallback) {};
 
 /**
  * @see http://www.w3.org/TR/file-system-api/#widl-LocalFileSystem-resolveLocalFileSystemURI
@@ -832,8 +620,8 @@ function resolveLocalFileSystemURI(uri, successCallback, errorCallback) {}
  * @param {function(!FileError)=} errorCallback
  * @return {undefined}
  */
-Window.prototype.resolveLocalFileSystemURI = function(uri, successCallback,
-    errorCallback) {}
+Window.prototype.resolveLocalFileSystemURI =
+    function(uri, successCallback, errorCallback) {}
 
 /**
  * This has replaced requestFileSystem in Chrome since WebKit revision 84224.
@@ -878,8 +666,8 @@ function webkitResolveLocalFileSystemURI(uri, successCallback, errorCallback) {}
  * @param {function(!FileError)=} errorCallback
  * @return {undefined}
  */
-Window.prototype.webkitResolveLocalFileSystemURI = function(uri, successCallback,
-    errorCallback) {}
+Window.prototype.webkitResolveLocalFileSystemURI = function(
+    uri, successCallback, errorCallback) {}
 
 // WindowBlobURIMethods interface, implemented by Window and WorkerGlobalScope.
 // There are three APIs for this: the old specced API, the new specced API, and
@@ -918,9 +706,9 @@ Window.prototype.revokeObjectURL = function(url) {};
  * This has been replaced by URL in Chrome since WebKit revision 75739.
  * @constructor
  * @param {string} urlString
- * @param {string=} opt_base
+ * @param {string=} base
  */
-function webkitURL(urlString, opt_base) {}
+function webkitURL(urlString, base) {}
 
 /**
  * @see http://www.w3.org/TR/FileAPI/#dfn-createObjectURL
@@ -944,15 +732,15 @@ function StorageInfo() {}
 
 /**
  * @see https://developers.google.com/chrome/whitepapers/storage
- * @type {number}
+ * @const {number}
  * */
-StorageInfo.prototype.TEMPORARY = 0;
+StorageInfo.prototype.TEMPORARY;
 
 /**
  * @see https://developers.google.com/chrome/whitepapers/storage
- * @type {number}
+ * @const {number}
  */
-StorageInfo.prototype.PERSISTENT = 1;
+StorageInfo.prototype.PERSISTENT;
 
 /**
  * @see https://developers.google.com/chrome/whitepapers/storage#requestQuota
@@ -962,8 +750,8 @@ StorageInfo.prototype.PERSISTENT = 1;
  * @param {function(!DOMException)=} errorCallback
  * @return {undefined}
  */
-StorageInfo.prototype.requestQuota = function(type, size, successCallback,
-    errorCallback) {};
+StorageInfo.prototype.requestQuota = function(
+    type, size, successCallback, errorCallback) {};
 
 /**
  * @see https://developers.google.com/chrome/whitepapers/storage#queryUsageAndQuota
@@ -972,8 +760,8 @@ StorageInfo.prototype.requestQuota = function(type, size, successCallback,
  * @param {function(!DOMException)=} errorCallback
  * @return {undefined}
  */
-StorageInfo.prototype.queryUsageAndQuota = function(type, successCallback,
-    errorCallback) {};
+StorageInfo.prototype.queryUsageAndQuota = function(
+    type, successCallback, errorCallback) {};
 
 /**
  * @see https://developers.google.com/chrome/whitepapers/storage
@@ -989,21 +777,20 @@ function StorageQuota() {}
 
 /**
  * @param {number} size
- * @param {function(number)=} opt_successCallback
- * @param {function(!DOMException)=} opt_errorCallback
+ * @param {function(number)=} successCallback
+ * @param {function(!DOMException)=} errorCallback
  * @return {undefined}
  */
-StorageQuota.prototype.requestQuota = function(size, opt_successCallback,
-    opt_errorCallback) {};
+StorageQuota.prototype.requestQuota = function(
+    size, successCallback, errorCallback) {};
 
 /**
  * @param {function(number, number)} successCallback
- * @param {function(!DOMException)=} opt_errorCallback
+ * @param {function(!DOMException)=} errorCallback
  * @return {undefined}
  */
-StorageQuota.prototype.queryUsageAndQuota = function(successCallback,
-    opt_errorCallback) {};
-
+StorageQuota.prototype.queryUsageAndQuota = function(
+    successCallback, errorCallback) {};
 
 /**
  * @type {!StorageQuota}
@@ -1016,3 +803,357 @@ Navigator.prototype.webkitPersistentStorage;
  * @see https://developer.chrome.com/apps/offline_storage
  */
 Navigator.prototype.webkitTemporaryStorage;
+
+
+/**
+ * @see http://www.w3.org/TR/file-writer-api/#idl-def-FileWriterSync
+ * @constructor
+ */
+function FileWriterSync() {}
+
+/**
+ * @see http://www.w3.org/TR/file-writer-api/#widl-FileWriterSync-position
+ * @type {number}
+ * @const
+ */
+FileWriterSync.prototype.position;
+
+/**
+ * @see http://www.w3.org/TR/file-writer-api/#widl-FileWriterSync-length
+ * @type {number}
+ * @const
+ */
+FileWriterSync.prototype.length;
+
+/**
+ * @see http://www.w3.org/TR/file-writer-api/#widl-FileWriter-write
+ * @param {!Blob} blob
+ * @return {undefined}
+ */
+FileWriterSync.prototype.write = function(blob) {};
+
+/**
+ * @see http://www.w3.org/TR/file-writer-api/#widl-FileWriterSync-seek
+ * @param {number} offset
+ * @return {undefined}
+ */
+FileWriterSync.prototype.seek = function(offset) {};
+
+/**
+ * @see http://www.w3.org/TR/file-writer-api/#widl-FileWriterSync-truncate
+ * @param {number} size
+ * @return {undefined}
+ */
+FileWriterSync.prototype.truncate = function(size) {};
+
+/**
+ * LocalFileSystemSync interface, implemented by WorkerGlobalScope.
+ * @see http://www.w3.org/TR/file-system-api/#idl-def-LocalFileSystemSync
+ * @constructor
+ */
+function LocalFileSystemSync() {}
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/
+ *     #the-synchronous-filesystem-interface
+ * @constructor
+ */
+function FileSystemSync() {}
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-FileSystemSync-name
+ * @type {string}
+ * @const
+ */
+FileSystemSync.prototype.name;
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-FileSystemSync-root
+ * @type {!DirectoryEntrySync}
+ * @const
+ */
+FileSystemSync.prototype.root;
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-LocalFileSystemSync-requestFileSystemSync-FileSystemSync-unsigned-short-type-unsigned-long-long-size
+ * @param {number} type
+ * @param {number} size
+ * @return {!FileSystemSync}
+ */
+function requestFileSystemSync(type, size) {}
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-LocalFileSystemSync-requestFileSystemSync-FileSystemSync-unsigned-short-type-unsigned-long-long-size
+ * @param {number} type
+ * @param {number} size
+ * @return {!FileSystemSync}
+ */
+function webkitRequestFileSystemSync(type, size) {}
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#the-entrysync-interface
+ * @constructor
+ */
+function EntrySync() {};
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-EntrySync-isFile
+ * @type {boolean}
+ * @const
+ */
+EntrySync.prototype.isFile;
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-EntrySync-isDirectory
+ * @type {boolean}
+ * @const
+ */
+EntrySync.prototype.isDirectory;
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-EntrySync-name
+ * @type {string}
+ * @const
+ */
+EntrySync.prototype.name;
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-EntrySync-fullPath
+ * @type {string}
+ * @const
+ */
+EntrySync.prototype.fullPath;
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-EntrySync-filesystem
+ * @type {!FileSystemSync}
+ * @const
+ */
+EntrySync.prototype.filesystem;
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-EntrySync-moveTo
+ * @param {!DirectoryEntrySync} parent
+ * @param {string=} newName
+ * @return {!EntrySync}
+ */
+EntrySync.prototype.moveTo = function(parent, newName) {};
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-EntrySync-copyTo
+ * @param {!DirectoryEntrySync} parent
+ * @param {string=} newName
+ * @return {!EntrySync}
+ */
+EntrySync.prototype.copyTo = function(parent, newName) {};
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-EntrySync-toURL
+ * @param {string=} mimeType
+ * @return {string}
+ */
+EntrySync.prototype.toURL = function(mimeType) {};
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-EntrySync-remove
+ * @return {undefined}
+ */
+EntrySync.prototype.remove = function() {};
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-EntrySync-getMetadata
+ * @return {!Metadata}
+ */
+EntrySync.prototype.getMetadata = function() {};
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-EntrySync-getParent
+ * @return {!DirectoryEntrySync}
+ */
+EntrySync.prototype.getParent = function() {};
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#the-directoryentrysync-interface
+ * @constructor
+ * @extends {EntrySync}
+ */
+function DirectoryEntrySync() {};
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-DirectoryEntrySync-createReader
+ * @return {!DirectoryReaderSync}
+ */
+DirectoryEntrySync.prototype.createReader = function() {};
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-DirectoryEntrySync-getFile
+ * @param {string} path
+ * @param {Object=} options
+ * @return {!FileEntrySync}
+ */
+DirectoryEntrySync.prototype.getFile = function(path, options) {};
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-DirectoryEntrySync-getDirectory
+ * @param {string} path
+ * @param {Object=} options
+ * @return {!DirectoryEntrySync}
+ */
+DirectoryEntrySync.prototype.getDirectory = function(path, options) {};
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-DirectoryEntrySync-removeRecursively
+ * @return {undefined}
+ */
+DirectoryEntrySync.prototype.removeRecursively = function() {};
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#the-directoryreadersync-interface
+ * @constructor
+ */
+function DirectoryReaderSync() {};
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-DirectoryReaderSync-readEntries
+ * @return {!Array<!EntrySync>}
+ */
+DirectoryReaderSync.prototype.readEntries = function() {};
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#the-fileentrysync-interface
+ * @constructor
+ * @extends {EntrySync}
+ */
+function FileEntrySync() {};
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-FileEntrySync-createWriter
+ * @return {!FileWriterSync}
+ */
+FileEntrySync.prototype.createWriter = function() {};
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-FileEntrySync-file
+ * @return {!File}
+ */
+FileEntrySync.prototype.file = function() {};
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#the-fileexception-exception
+ * @constructor
+ */
+function FileException() {}
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-NOT_FOUND_ERR
+ * @type {number}
+ */
+FileException.prototype.NOT_FOUND_ERR;
+
+/** @type {number} */
+FileException.NOT_FOUND_ERR;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-SECURITY_ERR
+ * @type {number}
+ */
+FileException.prototype.SECURITY_ERR;
+
+/** @type {number} */
+FileException.SECURITY_ERR;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#widl-FileException-ABORT_ERR
+ * @type {number}
+ */
+FileException.prototype.ABORT_ERR;
+
+/** @type {number} */
+FileException.ABORT_ERR;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#widl-FileException-NOT_READABLE_ERR
+ * @type {number}
+ */
+FileException.prototype.NOT_READABLE_ERR;
+
+/** @type {number} */
+FileException.NOT_READABLE_ERR;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#widl-FileException-ENCODING_ERR
+ * @type {number}
+ */
+FileException.prototype.ENCODING_ERR;
+
+/** @type {number} */
+FileException.ENCODING_ERR;
+
+/**
+ * @see http://www.w3.org/TR/file-writer-api/#widl-FileException-NO_MODIFICATION_ALLOWED_ERR
+ * @type {number}
+ */
+FileException.prototype.NO_MODIFICATION_ALLOWED_ERR;
+
+/** @type {number} */
+FileException.NO_MODIFICATION_ALLOWED_ERR;
+
+/**
+ * @see http://www.w3.org/TR/file-writer-api/#widl-FileException-INVALID_STATE_ERR
+ * @type {number}
+ */
+FileException.prototype.INVALID_STATE_ERR;
+
+/** @type {number} */
+FileException.INVALID_STATE_ERR;
+
+/**
+ * @see http://www.w3.org/TR/file-writer-api/#widl-FileException-SYNTAX_ERR
+ * @type {number}
+ */
+FileException.prototype.SYNTAX_ERR;
+
+/** @type {number} */
+FileException.SYNTAX_ERR;
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-FileException-INVALID_MODIFICATION_ERR
+ * @type {number}
+ */
+FileException.prototype.INVALID_MODIFICATION_ERR;
+
+/** @type {number} */
+FileException.INVALID_MODIFICATION_ERR;
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-FileException-QUOTA_EXCEEDED_ERR
+ * @type {number}
+ */
+FileException.prototype.QUOTA_EXCEEDED_ERR;
+
+/** @type {number} */
+FileException.QUOTA_EXCEEDED_ERR;
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-FileException-TYPE_MISMATCH_ERR
+ * @type {number}
+ */
+FileException.prototype.TYPE_MISMATCH_ERR;
+
+/** @type {number} */
+FileException.TYPE_MISMATCH_ERR;
+
+/**
+ * @see http://www.w3.org/TR/file-system-api/#widl-FileException-PATH_EXISTS_ERR
+ * @type {number}
+ */
+FileException.prototype.PATH_EXISTS_ERR;
+
+/** @type {number} */
+FileException.PATH_EXISTS_ERR;
+
+/**
+ * @see http://www.w3.org/TR/FileAPI/#dfn-code-exception
+ * @type {number}
+ */
+FileException.prototype.code;
diff --git a/javascript/externs/web/flash.js b/javascript/externs/web/flash.js
index c9e4d886f86a..014f3481af0a 100644
--- a/javascript/externs/web/flash.js
+++ b/javascript/externs/web/flash.js
@@ -39,12 +39,12 @@ HTMLObjectElement.prototype.CallFunction = function(xmlString) {};
  * Returns the value of the Flash variable specified by varName or null if the
  * variable does not exist.
  * @param {string} varName The variable name.
- * @return {string?} The variable value.
+ * @return {?string} The variable value.
  */
 HTMLObjectElement.prototype.GetVariable = function(varName) {};
 
 /**
- * Activates the frame number specified by {@code frameNumber} in the current
+ * Activates the frame number specified by `frameNumber` in the current
  * movie.
  * @param {number} frameNumber A non-negative integer frame number.
  * @return {undefined}
@@ -57,8 +57,8 @@ HTMLObjectElement.prototype.GotoFrame = function(frameNumber) {};
 HTMLObjectElement.prototype.IsPlaying = function() {};
 
 /**
- * Loads the movie identified by {@code url} to the layer specified by {@code
- * layerNumber}.
+ * Loads the movie identified by `url` to the layer specified by
+ * `layerNumber`.
  * @param {number} layerNumber The layer number.
  * @param {string} url The movie URL.
  * @return {undefined}
@@ -136,7 +136,7 @@ HTMLObjectElement.prototype.Zoom = function(percent) {};
 // TellTarget Methods.
 
 /**
- * Executes the action in the timeline specified by {@code target} in the
+ * Executes the action in the timeline specified by `target` in the
  * specified frame.
  * @param {string} target The timeline.
  * @param {number} frameNumber The frame number.
@@ -145,7 +145,7 @@ HTMLObjectElement.prototype.Zoom = function(percent) {};
 HTMLObjectElement.prototype.TCallFrame = function(target, frameNumber) {};
 
 /**
- * Executes the action in the timeline specified by {@code target} in the
+ * Executes the action in the timeline specified by `target` in the
  * specified frame.
  * @param {string} target The timeline.
  * @param {string} label The frame label.
diff --git a/javascript/externs/web/gecko_dom.js b/javascript/externs/web/gecko_dom.js
index 6e179cddf8c5..655640cee46b 100644
--- a/javascript/externs/web/gecko_dom.js
+++ b/javascript/externs/web/gecko_dom.js
@@ -47,12 +47,6 @@ Window.prototype.Components;
  */
 Window.prototype.content;
 
-/**
- * @type {boolean}
- * @see https://developer.mozilla.org/en/DOM/window.closed
- */
-Window.prototype.closed;
-
 /** @see https://developer.mozilla.org/en/DOM/window.controllers */
 Window.prototype.controllers;
 
@@ -72,19 +66,6 @@ Window.prototype.dialogArguments;
 /** @see https://developer.mozilla.org/en/DOM/window.directories */
 Window.prototype.directories;
 
-/**
- * @type {HTMLObjectElement|HTMLIFrameElement|null}
- * @see https://developer.mozilla.org/en/DOM/window.frameElement
- */
-Window.prototype.frameElement;
-
-/**
- * Allows lookup of frames by index or by name.
- * @type {?Object}
- * @see https://developer.mozilla.org/en/DOM/window.frames
- */
-Window.prototype.frames;
-
 /**
  * @type {boolean}
  * @see https://developer.mozilla.org/en/DOM/window.fullScreen
@@ -95,76 +76,77 @@ Window.prototype.fullScreen;
  * @return {!Promise<!BatteryManager>}
  * @see http://www.w3.org/TR/battery-status/
  */
-Navigator.prototype.getBattery = function() {};
-
-/**
- * @see https://developer.mozilla.org/en/DOM/Storage#globalStorage
- */
-Window.prototype.globalStorage;
-
-/**
- * @type {!History}
- * @suppress {duplicate}
- * @see https://developer.mozilla.org/en/DOM/window.history
- */
-var history;
-
-/**
- * Returns the number of frames (either frame or iframe elements) in the
- * window.
- *
- * @type {number}
- * @see https://developer.mozilla.org/en/DOM/window.length
- */
-Window.prototype.length;
-
-/**
- * Location has an exception in the DeclaredGlobalExternsOnWindow pass
- * so we have to manually include it:
- * https://github.com/google/closure-compiler/blob/master/src/com/google/javascript/jscomp/DeclaredGlobalExternsOnWindow.java#L116
- *
- * @type {!Location}
- * @implicitCast
- * @see https://developer.mozilla.org/en/DOM/window.location
- */
-Window.prototype.location;
-
-/**
- * @see https://developer.mozilla.org/en/DOM/window.locationbar
- */
-Window.prototype.locationbar;
-
-/**
- * @see https://developer.mozilla.org/en/DOM/window.menubar
- */
-Window.prototype.menubar;
-
-/**
- * @type {string}
- * @see https://developer.mozilla.org/en/DOM/window.name
- */
-Window.prototype.name;
-
-/**
- * @type {Navigator}
- * @see https://developer.mozilla.org/en/DOM/window.navigator
- */
-Window.prototype.navigator;
-
-/**
- * @type {?Window}
- * @see https://developer.mozilla.org/en/DOM/window.opener
- */
-Window.prototype.opener;
-
-/**
- * @type {!Window}
- * @see https://developer.mozilla.org/en/DOM/window.parent
- */
-Window.prototype.parent;
-
-/** @see https://developer.mozilla.org/en/DOM/window.personalbar */
-Window.prototype.personalbar;
+ Navigator.prototype.getBattery = function() {};
+
+ /**
+  * @see https://developer.mozilla.org/en/DOM/Storage#globalStorage
+  */
+ Window.prototype.globalStorage;
+ 
+ /**
+  * @type {!History}
+  * @suppress {duplicate}
+  * @see https://developer.mozilla.org/en/DOM/window.history
+  */
+ var history;
+ 
+ /**
+  * Returns the number of frames (either frame or iframe elements) in the
+  * window.
+  *
+  * @type {number}
+  * @see https://developer.mozilla.org/en/DOM/window.length
+  */
+ Window.prototype.length;
+ 
+ /**
+  * Location has an exception in the DeclaredGlobalExternsOnWindow pass
+  * so we have to manually include it:
+  * https://github.com/google/closure-compiler/blob/master/src/com/google/javascript/jscomp/DeclaredGlobalExternsOnWindow.java#L116
+  *
+  * @type {!Location}
+  * @implicitCast
+  * @see https://developer.mozilla.org/en/DOM/window.location
+  */
+ Window.prototype.location;
+ 
+ /**
+  * @see https://developer.mozilla.org/en/DOM/window.locationbar
+  */
+ Window.prototype.locationbar;
+ 
+ /**
+  * @see https://developer.mozilla.org/en/DOM/window.menubar
+  */
+ Window.prototype.menubar;
+ 
+ /**
+  * @type {string}
+  * @see https://developer.mozilla.org/en/DOM/window.name
+  */
+ Window.prototype.name;
+ 
+ /**
+  * @type {Navigator}
+  * @see https://developer.mozilla.org/en/DOM/window.navigator
+  */
+ Window.prototype.navigator;
+ 
+ /**
+  * @type {?Window}
+  * @see https://developer.mozilla.org/en/DOM/window.opener
+  */
+ Window.prototype.opener;
+ 
+ /**
+  * @type {!Window}
+  * @see https://developer.mozilla.org/en/DOM/window.parent
+  */
+ Window.prototype.parent;
+ 
+ /** @see https://developer.mozilla.org/en/DOM/window.personalbar */
+ Window.prototype.personalbar;
+ 
 
 /** @see https://developer.mozilla.org/en/DOM/window.pkcs11 */
 Window.prototype.pkcs11;
@@ -172,9 +154,6 @@ Window.prototype.pkcs11;
 /** @see https://developer.mozilla.org/en/DOM/window */
 Window.prototype.returnValue;
 
-/** @see https://developer.mozilla.org/en/DOM/window.scrollbars */
-Window.prototype.scrollbars;
-
 /**
  * @type {number}
  * @see https://developer.mozilla.org/En/DOM/window.scrollMaxX
@@ -187,59 +166,15 @@ Window.prototype.scrollMaxX;
  */
 Window.prototype.scrollMaxY;
 
-/**
- * @type {!Window}
- * @see https://developer.mozilla.org/en/DOM/window.self
- */
-Window.prototype.self;
-
-/** @see https://developer.mozilla.org/en/DOM/Storage#sessionStorage */
-Window.prototype.sessionStorage;
-
 /** @see https://developer.mozilla.org/en/DOM/window.sidebar */
 Window.prototype.sidebar;
 
-/**
- * @type {?string}
- * @see https://developer.mozilla.org/en/DOM/window.status
- */
-Window.prototype.status;
-
-/** @see https://developer.mozilla.org/en/DOM/window.statusbar */
-Window.prototype.statusbar;
-
-/** @see https://developer.mozilla.org/en/DOM/window.toolbar */
-Window.prototype.toolbar;
-
-/**
- * @type {!Window}
- * @see https://developer.mozilla.org/en/DOM/window.self
- */
-Window.prototype.top;
-
-/**
- * @type {!Window}
- * @see https://developer.mozilla.org/en/DOM/window.self
- */
-Window.prototype.window;
-
 /**
  * @param {*} message
  * @see https://developer.mozilla.org/en/DOM/window.alert
  * @return {undefined}
  */
-Window.prototype.alert = function(message) {};
-
-/**
- * Decodes a string of data which has been encoded using base-64 encoding.
- *
- * @param {string} encodedData
- * @return {string}
- * @see https://developer.mozilla.org/en/DOM/window.atob
- * @nosideeffects
- */
-function atob(encodedData) {}
-
+ Window.prototype.alert = function(message) {};
 /**
  * @see https://developer.mozilla.org/en/DOM/window.back
  * @return {undefined}
@@ -250,7 +185,7 @@ Window.prototype.back = function() {};
  * @see https://developer.mozilla.org/en/DOM/window.blur
  * @return {undefined}
  */
-Window.prototype.blur = function() {};
+ Window.prototype.blur = function() {};
 
 /**
  * @param {string} stringToEncode
@@ -267,17 +202,11 @@ Window.prototype.captureEvents;
  * @see https://developer.mozilla.org/en/DOM/window.close
  * @return {undefined}
  */
-Window.prototype.close = function() {};
+ Window.prototype.close = function() {};
 
 /**@see https://developer.mozilla.org/en/DOM/window.find */
 Window.prototype.find;
 
-/**
- * @see https://developer.mozilla.org/en/DOM/window.focus
- * @return {undefined}
- */
-Window.prototype.focus = function() {};
-
 /**
  * @see https://developer.mozilla.org/en/DOM/window.forward
  * @return {undefined}
@@ -290,13 +219,6 @@ Window.prototype.forward = function() {};
  */
 Window.prototype.getAttention = function() {};
 
-/**
- * @return {Selection}
- * @see https://developer.mozilla.org/en/DOM/window.getSelection
- * @nosideeffects
- */
-Window.prototype.getSelection = function() {};
-
 /**
  * @see https://developer.mozilla.org/en/DOM/window.home
  * @return {undefined}
@@ -318,12 +240,6 @@ Window.prototype.showModalDialog;
 
 Window.prototype.sizeToContent;
 
-/**
- * @see http://msdn.microsoft.com/en-us/library/ms536769(VS.85).aspx
- * @return {undefined}
- */
-Window.prototype.stop = function() {};
-
 Window.prototype.updateCommands;
 
 // properties of Document
@@ -345,8 +261,7 @@ Document.prototype.anchors;
  * @type {HTMLCollection<!HTMLAppletElement>}
  */
 Document.prototype.applets;
-/** @type {boolean} */ Document.prototype.async;
-/** @type {string?} */ Document.prototype.baseURI;
+/** @type {?string} */ Document.prototype.baseURI;
 
 /**
  * @see https://developer.mozilla.org/en/DOM/document.bgColor
@@ -365,6 +280,11 @@ Document.prototype.compatMode;
 
 Document.prototype.contentType;
 /** @type {string} */ Document.prototype.cookie;
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/Document/defaultView
+ * @type {?Window}
+ */
 Document.prototype.defaultView;
 
 /**
@@ -401,9 +321,6 @@ Document.prototype.fgColor;
  */
 Document.prototype.forms;
 
-/** @type {number} */
-Document.prototype.height;
-
 /** @type {HTMLCollection<!HTMLImageElement>} */
 Document.prototype.images;
 
@@ -467,11 +384,6 @@ Document.prototype.vlinkColor;
  */
 Document.prototype.clear = function() {};
 
-/**
- * @see https://developer.mozilla.org/en/DOM/document.close
- */
-Document.prototype.close;
-
 /**
  * @param {string} type
  * @return {Event}
@@ -491,26 +403,8 @@ Document.prototype.evaluate;
  */
 Document.prototype.execCommand;
 
-/**
- * @param {string} name
- * @return {!NodeList<!Element>}
- * @nosideeffects
- * @see https://developer.mozilla.org/en/DOM/document.getElementsByClassName
- */
-Document.prototype.getElementsByClassName = function(name) {};
-
-/**
- * @param {string} uri
- * @return {undefined}
- */
-Document.prototype.load = function(uri) {};
 Document.prototype.loadOverlay;
 
-/**
- * @see https://developer.mozilla.org/en/DOM/document.open
- */
-Document.prototype.open;
-
 /**
  * @see https://developer.mozilla.org/en/Midas
  * @see http://msdn.microsoft.com/en-us/library/ms536676(VS.85).aspx
@@ -556,7 +450,7 @@ Document.prototype.write = function(text) {};
  * @return {undefined}
  */
 Document.prototype.writeln = function(text) {};
-
+ 
 Document.prototype.ononline;
 Document.prototype.onoffline;
 
@@ -572,7 +466,7 @@ Document.prototype.getBoxObjectFor = function(element) {};
 // http://lxr.mozilla.org/mozilla1.8/source/dom/public/idl/range/nsIDOMNSRange.idl
 
 /**
- * @param {string} tag
+ * @param {!TrustedHTML|string} tag
  * @return {DocumentFragment}
  */
 Range.prototype.createContextualFragment;
@@ -607,128 +501,6 @@ Range.prototype.intersectsNode;
  */
 Range.prototype.compareNode;
 
-
-/** @constructor */
-function Selection() {}
-
-/**
- * @type {Node}
- * @see https://developer.mozilla.org/en/DOM/Selection/anchorNode
- */
-Selection.prototype.anchorNode;
-
-/**
- * @type {number}
- * @see https://developer.mozilla.org/en/DOM/Selection/anchorOffset
- */
-Selection.prototype.anchorOffset;
-
-/**
- * @type {Node}
- * @see https://developer.mozilla.org/en/DOM/Selection/focusNode
- */
-Selection.prototype.focusNode;
-
-/**
- * @type {number}
- * @see https://developer.mozilla.org/en/DOM/Selection/focusOffset
- */
-Selection.prototype.focusOffset;
-
-/**
- * @type {boolean}
- * @see https://developer.mozilla.org/en/DOM/Selection/isCollapsed
- */
-Selection.prototype.isCollapsed;
-
-/**
- * @type {number}
- * @see https://developer.mozilla.org/en/DOM/Selection/rangeCount
- */
-Selection.prototype.rangeCount;
-
-/**
- * @param {Range} range
- * @return {undefined}
- * @see https://developer.mozilla.org/en/DOM/Selection/addRange
- */
-Selection.prototype.addRange = function(range) {};
-
-/**
- * @param {number} index
- * @return {Range}
- * @see https://developer.mozilla.org/en/DOM/Selection/getRangeAt
- * @nosideeffects
- */
-Selection.prototype.getRangeAt = function(index) {};
-
-/**
- * @param {Node} node
- * @param {number} index
- * @return {undefined}
- * @see https://developer.mozilla.org/en/DOM/Selection/collapse
- */
-Selection.prototype.collapse = function(node, index) {};
-
-/**
- * @return {undefined}
- * @see https://developer.mozilla.org/en/DOM/Selection/collapseToEnd
- */
-Selection.prototype.collapseToEnd = function() {};
-
-/**
- * @return {undefined}
- * @see https://developer.mozilla.org/en/DOM/Selection/collapseToStart
- */
-Selection.prototype.collapseToStart = function() {};
-
-/**
- * @param {Node} node
- * @param {boolean} partlyContained
- * @return {boolean}
- * @see https://developer.mozilla.org/en/DOM/Selection/containsNode
- * @nosideeffects
- */
-Selection.prototype.containsNode = function(node, partlyContained) {};
-
-/**
- * @see https://developer.mozilla.org/en/DOM/Selection/deleteFromDocument
- * @return {undefined}
- */
-Selection.prototype.deleteFromDocument = function() {};
-
-/**
- * @param {Node} parentNode
- * @param {number} offset
- * @see https://developer.mozilla.org/en/DOM/Selection/extend
- * @return {undefined}
- */
-Selection.prototype.extend = function(parentNode, offset) {};
-
-/**
- * @see https://developer.mozilla.org/en/DOM/Selection/removeAllRanges
- * @return {undefined}
- */
-Selection.prototype.removeAllRanges = function() {};
-
-/**
- * @param {Range} range
- * @see https://developer.mozilla.org/en/DOM/Selection/removeRange
- * @return {undefined}
- */
-Selection.prototype.removeRange = function(range) {};
-
-/**
- * @param {Node} parentNode
- * @see https://developer.mozilla.org/en/DOM/Selection/selectAllChildren
- */
-Selection.prototype.selectAllChildren;
-
-/**
- * @see https://developer.mozilla.org/en/DOM/Selection/selectionLanguageChange
- */
-Selection.prototype.selectionLanguageChange;
-
 /**
  * @type {!NodeList<!Element>}
  * @see https://developer.mozilla.org/en/DOM/element.children
@@ -741,22 +513,6 @@ Element.prototype.children;
  */
 Element.prototype.firebugIgnore;
 
-/**
- * Note: According to the spec, id is actually defined on HTMLElement and
- * SVGElement, rather than Element. Deliberately ignore this so that saying
- * Element.id is allowed.
- * @type {string}
- * @implicitCast
- */
-Element.prototype.id;
-
-/**
- * @type {string}
- * @see http://www.w3.org/TR/DOM-Parsing/#widl-Element-innerHTML
- * @implicitCast
- */
-Element.prototype.innerHTML;
-
 /**
  * Note: According to the spec, name is defined on specific types of
  * HTMLElements, rather than on Node, Element, or HTMLElement directly.
@@ -775,26 +531,14 @@ Element.prototype.nodePrincipal;
  */
 Element.prototype.style;
 
-/**
- * @override
- * @return {!Element}
- */
-Element.prototype.cloneNode = function(deep) {};
-
-/** @return {undefined} */
-Element.prototype.blur = function() {};
-
 /** @return {undefined} */
 Element.prototype.click = function() {};
 
-/** @return {undefined} */
-Element.prototype.focus = function() {};
-
 /** @type {number} */
-HTMLInputElement.prototype.selectionStart;
+HTMLTextAreaElement.prototype.selectionStart;
 
 /** @type {number} */
-HTMLInputElement.prototype.selectionEnd;
+HTMLTextAreaElement.prototype.selectionEnd;
 
 /**
  * @param {number} selectionStart
@@ -802,23 +546,19 @@ HTMLInputElement.prototype.selectionEnd;
  * @see http://www.whatwg.org/specs/web-apps/current-work/multipage/editing.html#dom-textarea/input-setselectionrange
  * @return {undefined}
  */
-HTMLInputElement.prototype.setSelectionRange =
+HTMLTextAreaElement.prototype.setSelectionRange =
     function(selectionStart, selectionEnd) {};
 
-/** @type {number} */
-HTMLTextAreaElement.prototype.selectionStart;
-
-/** @type {number} */
-HTMLTextAreaElement.prototype.selectionEnd;
-
 /**
- * @param {number} selectionStart
- * @param {number} selectionEnd
- * @see http://www.whatwg.org/specs/web-apps/current-work/multipage/editing.html#dom-textarea/input-setselectionrange
+ * @param {string} replacement
+ * @param {number=} start
+ * @param {number=} end
+ * @param {string=} selectionMode
+ * @see https://html.spec.whatwg.org/#dom-textarea/input-setrangetext
  * @return {undefined}
  */
-HTMLTextAreaElement.prototype.setSelectionRange =
-    function(selectionStart, selectionEnd) {};
+HTMLTextAreaElement.prototype.setRangeText =
+    function(replacement, start, end, selectionMode) {};
 
 /**
  * @type {string}
@@ -852,7 +592,7 @@ Navigator.prototype.securityPolicy;
 
 /**
  * @param {string} url
- * @param {ArrayBufferView|Blob|string|FormData=} opt_data
+ * @param {ArrayBufferView|Blob|string|FormData|URLSearchParams=} opt_data
  * @return {boolean}
  * @see https://developer.mozilla.org/en-US/docs/Web/API/navigator.sendBeacon
  */
diff --git a/javascript/externs/web/gecko_event.js b/javascript/externs/web/gecko_event.js
index e630d7f52cce..45335022b3c3 100644
--- a/javascript/externs/web/gecko_event.js
+++ b/javascript/externs/web/gecko_event.js
@@ -24,12 +24,11 @@
 
 // TODO: Almost all of it has not been annotated with types.
 
-/** @type {number} */ Event.prototype.HORIZONTAL_AXIS;
-/** @type {number} */ Event.prototype.VERTICAL_AXIS;
+/** @const {number} */ Event.prototype.HORIZONTAL_AXIS;
+/** @const {number} */ Event.prototype.VERTICAL_AXIS;
 /** @type {boolean} */ Event.prototype.altKey;
 /** @type {number} */ Event.prototype.axis;
 /** @type {number} */ Event.prototype.button;
-/** @type {boolean} */ Event.prototype.cancelBubble;
 /** @type {number} */ Event.prototype.charCode;
 /** @type {number} */ Event.prototype.clientX;
 /** @type {number} */ Event.prototype.clientY;
@@ -51,12 +50,36 @@
 /** @type {Window} */ Event.prototype.view;
 /** @type {number} */ Event.prototype.which;
 
+/**
+ * @type {boolean}
+ * @deprecated cancelBubble is obsolete and is no-op in modern browsers. Use
+ *     stopPropagation() instead.
+ */
+Event.prototype.cancelBubble;
+
 /** @constructor */ function nsIDOMPageTransitionEvent() {}
 /** @type {boolean} */ nsIDOMPageTransitionEvent.prototype.persisted;
 
 //Methods
 Event.prototype.initKeyEvent;
-Event.prototype.initMouseEvent;
+/**
+ * @param {string} typeArg
+ * @param {boolean=} canBubbleArg
+ * @param {boolean=} cancelableArg
+ * @param {?Window=} viewArg
+ * @param {?number=} detailArg
+ * @param {number=} screenXArg
+ * @param {number=} screenYArg
+ * @param {number=} clientXArg
+ * @param {number=} clientYArg
+ * @param {boolean=} ctrlKeyArg
+ * @param {boolean=} altKeyArg
+ * @param {boolean=} shiftKeyArg
+ * @param {boolean=} metaKeyArg
+ * @param {?number=} buttonArg
+ * @param {?EventTarget=} relatedTargetArg
+ */
+Event.prototype.initMouseEvent = function(typeArg, canBubbleArg, cancelableArg, viewArg, detailArg, screenXArg, screenYArg, clientXArg, clientYArg, ctrlKeyArg, altKeyArg, shiftKeyArg, metaKeyArg, buttonArg, relatedTargetArg) {};
 Event.prototype.initUIEvent;
 Event.prototype.initMessageEvent;
 Event.prototype.preventBubble;
diff --git a/javascript/externs/web/gecko_xml.js b/javascript/externs/web/gecko_xml.js
index ccab53d6729f..6d44e7da27d1 100644
--- a/javascript/externs/web/gecko_xml.js
+++ b/javascript/externs/web/gecko_xml.js
@@ -66,8 +66,8 @@ function DOMParser() {}
  *  var parser = new DOMParser();
  *  var doc = parser.parseFromString(aStr, "text/xml");
  *
- * @param {string} src The UTF16 string to be parsed.
+ * @param {!TrustedHTML|string} src The UTF16 string to be parsed.
  * @param {string} type The content type of the string.
- * @return {Document}
+ * @return {!Document}
  */
 DOMParser.prototype.parseFromString = function(src, type) {};
diff --git a/javascript/externs/web/html5.js b/javascript/externs/web/html5.js
index dacb3abeaf61..133fa7813b1a 100644
--- a/javascript/externs/web/html5.js
+++ b/javascript/externs/web/html5.js
@@ -29,6 +29,14 @@
  * @externs
  */
 
+/** @type {?HTMLSlotElement} */
+Node.prototype.assignedSlot;
+
+/**
+ * @type {string}
+ * @see https://dom.spec.whatwg.org/#dom-element-slot
+ */
+Element.prototype.slot;
 
 /**
  * Note: In IE, the contains() method only exists on Elements, not Nodes.
@@ -43,6 +51,38 @@
  */
 Node.prototype.contains = function(n) {};
 
+/** @type {boolean} */
+Node.prototype.isConnected;
+
+/**
+ * @type {boolean}
+ * @see https://html.spec.whatwg.org/multipage/scripting.html#the-script-element
+ */
+HTMLScriptElement.prototype.async;
+
+/**
+ * @type {string?}
+ * @see https://html.spec.whatwg.org/multipage/scripting.html#the-script-element
+ */
+HTMLScriptElement.prototype.crossOrigin;
+
+/**
+ * @type {string}
+ * @see https://html.spec.whatwg.org/multipage/scripting.html#the-script-element
+ */
+HTMLScriptElement.prototype.integrity;
+
+/**
+ * @type {boolean}
+ * @see https://html.spec.whatwg.org/multipage/scripting.html#the-script-element
+ */
+HTMLScriptElement.prototype.noModule;
+
+/**
+ * @type {string}
+ * @see https://html.spec.whatwg.org/multipage/scripting.html#the-script-element
+ */
+HTMLScriptElement.prototype.referrerPolicy;
 
 /**
  * @constructor
@@ -75,6 +115,7 @@ HTMLCanvasElement.prototype.toBlob = function(callback, opt_type, var_args) {};
 HTMLCanvasElement.prototype.toDataURL = function(opt_type, var_args) {};
 
 /**
+ * @modifies {this}
  * @param {string} contextId
  * @param {Object=} opt_args
  * @return {Object}
@@ -89,11 +130,95 @@ HTMLCanvasElement.prototype.getContext = function(contextId, opt_args) {};
  * */
 HTMLCanvasElement.prototype.captureStream = function(opt_framerate) {};
 
+/**
+ * @see https://html.spec.whatwg.org/multipage/canvas.html#dom-canvas-transfercontroltooffscreen
+ * @return {!OffscreenCanvas}
+ * @throws {Error}
+ * */
+HTMLCanvasElement.prototype.transferControlToOffscreen = function() {};
+
+
+/**
+ * @interface
+ * @extends {MediaStreamTrack}
+ * @see https://w3c.github.io/mediacapture-fromelement/#the-canvascapturemediastreamtrack
+ */
+function CanvasCaptureMediaStreamTrack() {}
+
+/**
+ * The canvas element that this media stream captures.
+ * @type {!HTMLCanvasElement}
+ */
+CanvasCaptureMediaStreamTrack.prototype.canvas;
+
+/**
+ * Allows applications to manually request that a frame from the canvas be
+ * captured and rendered into the track.
+ * @return {undefined}
+ */
+CanvasCaptureMediaStreamTrack.prototype.requestFrame = function() {};
+
+
+/**
+ * @see https://html.spec.whatwg.org/multipage/canvas.html#the-offscreencanvas-interface
+ * @implements {EventTarget}
+ * @implements {Transferable}
+ * @param {number} width
+ * @param {number} height
+ * @nosideeffects
+ * @constructor
+ */
+function OffscreenCanvas(width, height) {}
+
+/** @override */
+OffscreenCanvas.prototype.addEventListener = function(
+    type, listener, opt_options) {};
+
+/** @override */
+OffscreenCanvas.prototype.removeEventListener = function(
+    type, listener, opt_options) {};
+
+/** @override */
+OffscreenCanvas.prototype.dispatchEvent = function(evt) {};
+
+/** @type {number} */
+OffscreenCanvas.prototype.width;
+
+/** @type {number} */
+OffscreenCanvas.prototype.height;
+
+/**
+ * @param {string} contextId
+ * @param {!Object=} opt_options
+ * @modifies {this}
+ * @return {!Object}
+ */
+OffscreenCanvas.prototype.getContext = function(contextId, opt_options) {};
+
+/**
+ * @return {!ImageBitmap}
+ */
+OffscreenCanvas.prototype.transferToImageBitmap = function() {};
+
+/**
+ * @param {{type: (string|undefined), quality: (number|undefined)}=} opt_options
+ * @return {!Promise<!Blob>}
+ */
+OffscreenCanvas.prototype.convertToBlob = function(opt_options) {};
+
+// TODO(tjgq): Find a way to add SVGImageElement to this typedef without making
+// svg.js part of core.
+/**
+ * @typedef {HTMLImageElement|HTMLVideoElement|HTMLCanvasElement|ImageBitmap|
+ *     OffscreenCanvas}
+ */
+var CanvasImageSource;
+
 /**
  * @interface
  * @see https://www.w3.org/TR/2dcontext/#canvaspathmethods
  */
-function CanvasPathMethods() {};
+function CanvasPathMethods() {}
 
 /**
  * @return {undefined}
@@ -166,46 +291,179 @@ CanvasPathMethods.prototype.rect = function(x, y, w, h) {};
 CanvasPathMethods.prototype.arc = function(
     x, y, radius, startAngle, endAngle, opt_anticlockwise) {};
 
+/**
+ * @constructor
+ * @param {!Path2D|string=} arg
+ * @implements {CanvasPathMethods}
+ * @see https://html.spec.whatwg.org/multipage/scripting.html#path2d-objects
+ */
+function Path2D(arg) {}
+
+/**
+ * @return {undefined}
+ * @override
+ */
+Path2D.prototype.closePath = function() {};
+
+/**
+ * @param {number} x
+ * @param {number} y
+ * @return {undefined}
+ * @override
+ */
+Path2D.prototype.moveTo = function(x, y) {};
+
+/**
+ * @param {number} x
+ * @param {number} y
+ * @return {undefined}
+ * @override
+ */
+Path2D.prototype.lineTo = function(x, y) {};
+
+/**
+ * @param {number} cpx
+ * @param {number} cpy
+ * @param {number} x
+ * @param {number} y
+ * @return {undefined}
+ * @override
+ */
+Path2D.prototype.quadraticCurveTo = function(cpx, cpy, x, y) {};
+
+/**
+ * @param {number} cp1x
+ * @param {number} cp1y
+ * @param {number} cp2x
+ * @param {number} cp2y
+ * @param {number} x
+ * @param {number} y
+ * @return {undefined}
+ * @override
+ */
+Path2D.prototype.bezierCurveTo = function(
+    cp1x, cp1y, cp2x, cp2y, x, y) {};
+
+/**
+ * @param {number} x1
+ * @param {number} y1
+ * @param {number} x2
+ * @param {number} y2
+ * @param {number} radius
+ * @return {undefined}
+ * @override
+ */
+Path2D.prototype.arcTo = function(x1, y1, x2, y2, radius) {};
+
+/**
+ * @param {number} x
+ * @param {number} y
+ * @param {number} w
+ * @param {number} h
+ * @return {undefined}
+ * @override
+ */
+Path2D.prototype.rect = function(x, y, w, h) {};
+
+/**
+ * @param {number} x
+ * @param {number} y
+ * @param {number} radius
+ * @param {number} startAngle
+ * @param {number} endAngle
+ * @param {boolean=} optAnticlockwise
+ * @return {undefined}
+ * @override
+ */
+Path2D.prototype.arc = function(
+    x, y, radius, startAngle, endAngle, optAnticlockwise) {};
+
+/**
+ * @param {Path2D} path
+ * @return {undefined}
+ */
+Path2D.prototype.addPath = function(path) {};
+
+/**
+ * @interface
+ * @see https://www.w3.org/TR/2dcontext/#canvasdrawingstyles
+ */
+function CanvasDrawingStyles() {}
+
+/** @type {number} */
+CanvasDrawingStyles.prototype.lineWidth;
+
+/** @type {string} */
+CanvasDrawingStyles.prototype.lineCap;
+
+/** @type {string} */
+CanvasDrawingStyles.prototype.lineJoin;
+
+/** @type {number} */
+CanvasDrawingStyles.prototype.miterLimit;
+
+/**
+ * @param {Array<number>} segments
+ * @return {undefined}
+ */
+CanvasDrawingStyles.prototype.setLineDash = function(segments) {};
+
+/**
+ * @return {!Array<number>}
+ */
+CanvasDrawingStyles.prototype.getLineDash = function() {};
+
+/** @type {string} */
+CanvasDrawingStyles.prototype.font;
+
+/** @type {string} */
+CanvasDrawingStyles.prototype.textAlign;
+
+/** @type {string} */
+CanvasDrawingStyles.prototype.textBaseline;
 
+// TODO(dramaix): replace this with @record.
 /**
  * @constructor
+ * @abstract
+ * @implements {CanvasDrawingStyles}
  * @implements {CanvasPathMethods}
  * @see http://www.w3.org/TR/2dcontext/#canvasrenderingcontext2d
  */
-function CanvasRenderingContext2D() {}
+function BaseRenderingContext2D() {}
 
-/** @type {!HTMLCanvasElement} */
-CanvasRenderingContext2D.prototype.canvas;
+/** @const {!HTMLCanvasElement|!OffscreenCanvas} */
+BaseRenderingContext2D.prototype.canvas;
 
 /**
  * @return {undefined}
  */
-CanvasRenderingContext2D.prototype.save = function() {};
+BaseRenderingContext2D.prototype.save = function() {};
 
 /**
  * @return {undefined}
  */
-CanvasRenderingContext2D.prototype.restore = function() {};
+BaseRenderingContext2D.prototype.restore = function() {};
 
 /**
  * @param {number} x
  * @param {number} y
  * @return {undefined}
  */
-CanvasRenderingContext2D.prototype.scale = function(x, y) {};
+BaseRenderingContext2D.prototype.scale = function(x, y) {};
 
 /**
  * @param {number} angle
  * @return {undefined}
  */
-CanvasRenderingContext2D.prototype.rotate = function(angle) {};
+BaseRenderingContext2D.prototype.rotate = function(angle) {};
 
 /**
  * @param {number} x
  * @param {number} y
  * @return {undefined}
  */
-CanvasRenderingContext2D.prototype.translate = function(x, y) {};
+BaseRenderingContext2D.prototype.translate = function(x, y) {};
 
 /**
  * @param {number} m11
@@ -216,7 +474,7 @@ CanvasRenderingContext2D.prototype.translate = function(x, y) {};
  * @param {number} dy
  * @return {undefined}
  */
-CanvasRenderingContext2D.prototype.transform = function(
+BaseRenderingContext2D.prototype.transform = function(
     m11, m12, m21, m22, dx, dy) {};
 
 /**
@@ -228,7 +486,7 @@ CanvasRenderingContext2D.prototype.transform = function(
  * @param {number} dy
  * @return {undefined}
  */
-CanvasRenderingContext2D.prototype.setTransform = function(
+BaseRenderingContext2D.prototype.setTransform = function(
     m11, m12, m21, m22, dx, dy) {};
 
 /**
@@ -236,10 +494,10 @@ CanvasRenderingContext2D.prototype.setTransform = function(
  * @param {number} y0
  * @param {number} x1
  * @param {number} y1
- * @return {CanvasGradient}
+ * @return {!CanvasGradient}
  * @throws {Error}
  */
-CanvasRenderingContext2D.prototype.createLinearGradient = function(
+BaseRenderingContext2D.prototype.createLinearGradient = function(
     x0, y0, x1, y1) {};
 
 /**
@@ -249,19 +507,20 @@ CanvasRenderingContext2D.prototype.createLinearGradient = function(
  * @param {number} x1
  * @param {number} y1
  * @param {number} r1
- * @return {CanvasGradient}
+ * @return {!CanvasGradient}
  * @throws {Error}
  */
-CanvasRenderingContext2D.prototype.createRadialGradient = function(
+BaseRenderingContext2D.prototype.createRadialGradient = function(
     x0, y0, r0, x1, y1, r1) {};
 
 /**
- * @param {HTMLImageElement|HTMLCanvasElement} image
+ * @param {CanvasImageSource} image
  * @param {string} repetition
- * @return {CanvasPattern}
+ * @return {?CanvasPattern}
  * @throws {Error}
+ * @see https://html.spec.whatwg.org/multipage/scripting.html#dom-context-2d-createpattern
  */
-CanvasRenderingContext2D.prototype.createPattern = function(
+BaseRenderingContext2D.prototype.createPattern = function(
     image, repetition) {};
 
 /**
@@ -271,7 +530,7 @@ CanvasRenderingContext2D.prototype.createPattern = function(
  * @param {number} h
  * @return {undefined}
  */
-CanvasRenderingContext2D.prototype.clearRect = function(x, y, w, h) {};
+BaseRenderingContext2D.prototype.clearRect = function(x, y, w, h) {};
 
 /**
  * @param {number} x
@@ -280,7 +539,7 @@ CanvasRenderingContext2D.prototype.clearRect = function(x, y, w, h) {};
  * @param {number} h
  * @return {undefined}
  */
-CanvasRenderingContext2D.prototype.fillRect = function(x, y, w, h) {};
+BaseRenderingContext2D.prototype.fillRect = function(x, y, w, h) {};
 
 /**
  * @param {number} x
@@ -289,18 +548,18 @@ CanvasRenderingContext2D.prototype.fillRect = function(x, y, w, h) {};
  * @param {number} h
  * @return {undefined}
  */
-CanvasRenderingContext2D.prototype.strokeRect = function(x, y, w, h) {};
+BaseRenderingContext2D.prototype.strokeRect = function(x, y, w, h) {};
 
 /**
  * @return {undefined}
  */
-CanvasRenderingContext2D.prototype.beginPath = function() {};
+BaseRenderingContext2D.prototype.beginPath = function() {};
 
 /**
  * @return {undefined}
  * @override
  */
-CanvasRenderingContext2D.prototype.closePath = function() {};
+BaseRenderingContext2D.prototype.closePath = function() {};
 
 /**
  * @param {number} x
@@ -308,7 +567,7 @@ CanvasRenderingContext2D.prototype.closePath = function() {};
  * @return {undefined}
  * @override
  */
-CanvasRenderingContext2D.prototype.moveTo = function(x, y) {};
+BaseRenderingContext2D.prototype.moveTo = function(x, y) {};
 
 /**
  * @param {number} x
@@ -316,7 +575,7 @@ CanvasRenderingContext2D.prototype.moveTo = function(x, y) {};
  * @return {undefined}
  * @override
  */
-CanvasRenderingContext2D.prototype.lineTo = function(x, y) {};
+BaseRenderingContext2D.prototype.lineTo = function(x, y) {};
 
 /**
  * @param {number} cpx
@@ -326,7 +585,7 @@ CanvasRenderingContext2D.prototype.lineTo = function(x, y) {};
  * @return {undefined}
  * @override
  */
-CanvasRenderingContext2D.prototype.quadraticCurveTo = function(
+BaseRenderingContext2D.prototype.quadraticCurveTo = function(
     cpx, cpy, x, y) {};
 
 /**
@@ -339,7 +598,7 @@ CanvasRenderingContext2D.prototype.quadraticCurveTo = function(
  * @return {undefined}
  * @override
  */
-CanvasRenderingContext2D.prototype.bezierCurveTo = function(
+BaseRenderingContext2D.prototype.bezierCurveTo = function(
     cp1x, cp1y, cp2x, cp2y, x, y) {};
 
 /**
@@ -351,7 +610,7 @@ CanvasRenderingContext2D.prototype.bezierCurveTo = function(
  * @return {undefined}
  * @override
  */
-CanvasRenderingContext2D.prototype.arcTo = function(x1, y1, x2, y2, radius) {};
+BaseRenderingContext2D.prototype.arcTo = function(x1, y1, x2, y2, radius) {};
 
 /**
  * @param {number} x
@@ -361,7 +620,7 @@ CanvasRenderingContext2D.prototype.arcTo = function(x1, y1, x2, y2, radius) {};
  * @return {undefined}
  * @override
  */
-CanvasRenderingContext2D.prototype.rect = function(x, y, w, h) {};
+BaseRenderingContext2D.prototype.rect = function(x, y, w, h) {};
 
 /**
  * @param {number} x
@@ -373,7 +632,7 @@ CanvasRenderingContext2D.prototype.rect = function(x, y, w, h) {};
  * @return {undefined}
  * @override
  */
-CanvasRenderingContext2D.prototype.arc = function(
+BaseRenderingContext2D.prototype.arc = function(
     x, y, radius, startAngle, endAngle, opt_anticlockwise) {};
 
 /**
@@ -388,26 +647,35 @@ CanvasRenderingContext2D.prototype.arc = function(
  * @return {undefined}
  * @see http://developer.mozilla.org/en/docs/Web/API/CanvasRenderingContext2D/ellipse
  */
-CanvasRenderingContext2D.prototype.ellipse = function(
+BaseRenderingContext2D.prototype.ellipse = function(
     x, y, radiusX, radiusY, rotation, startAngle, endAngle, opt_anticlockwise) {
 };
 
 /**
- * @param {string=} opt_fillRule
+ * @param {Path2D|string=} optFillRuleOrPath
+ * @param {string=} optFillRule
  * @return {undefined}
  */
-CanvasRenderingContext2D.prototype.fill = function(opt_fillRule) {};
+BaseRenderingContext2D.prototype.fill = function(optFillRuleOrPath, optFillRule) {};
 
 /**
+ * @param {Path2D=} optStroke
  * @return {undefined}
  */
-CanvasRenderingContext2D.prototype.stroke = function() {};
+BaseRenderingContext2D.prototype.stroke = function(optStroke) {};
 
 /**
- * @param {string=} opt_fillRule
+ * @param {Element} element
+ * @return {undefined}
+ */
+BaseRenderingContext2D.prototype.drawFocusIfNeeded = function(element) {};
+
+/**
+ * @param {Path2D|string=} optFillRuleOrPath
+ * @param {string=} optFillRule
  * @return {undefined}
  */
-CanvasRenderingContext2D.prototype.clip = function(opt_fillRule) {};
+BaseRenderingContext2D.prototype.clip = function(optFillRuleOrPath, optFillRule) {};
 
 /**
  * @param {number} x
@@ -416,7 +684,7 @@ CanvasRenderingContext2D.prototype.clip = function(opt_fillRule) {};
  * @nosideeffects
  * @see http://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/isPointInStroke
  */
-CanvasRenderingContext2D.prototype.isPointInStroke = function(x, y) {};
+BaseRenderingContext2D.prototype.isPointInStroke = function(x, y) {};
 
 /**
  * @param {number} x
@@ -425,7 +693,7 @@ CanvasRenderingContext2D.prototype.isPointInStroke = function(x, y) {};
  * @return {boolean}
  * @nosideeffects
  */
-CanvasRenderingContext2D.prototype.isPointInPath = function(
+BaseRenderingContext2D.prototype.isPointInPath = function(
     x, y, opt_fillRule) {};
 
 /**
@@ -435,7 +703,7 @@ CanvasRenderingContext2D.prototype.isPointInPath = function(
  * @param {number=} opt_maxWidth
  * @return {undefined}
  */
-CanvasRenderingContext2D.prototype.fillText = function(
+BaseRenderingContext2D.prototype.fillText = function(
     text, x, y, opt_maxWidth) {};
 
 /**
@@ -445,18 +713,18 @@ CanvasRenderingContext2D.prototype.fillText = function(
  * @param {number=} opt_maxWidth
  * @return {undefined}
  */
-CanvasRenderingContext2D.prototype.strokeText = function(
+BaseRenderingContext2D.prototype.strokeText = function(
     text, x, y, opt_maxWidth) {};
 
 /**
  * @param {string} text
- * @return {TextMetrics}
+ * @return {!TextMetrics}
  * @nosideeffects
  */
-CanvasRenderingContext2D.prototype.measureText = function(text) {};
+BaseRenderingContext2D.prototype.measureText = function(text) {};
 
 /**
- * @param {HTMLImageElement|HTMLCanvasElement|Image|HTMLVideoElement} image
+ * @param {CanvasImageSource} image
  * @param {number} dx Destination x coordinate.
  * @param {number} dy Destination y coordinate.
  * @param {number=} opt_dw Destination box width.  Defaults to the image width.
@@ -472,26 +740,27 @@ CanvasRenderingContext2D.prototype.measureText = function(text) {};
  *     the source image to draw.  Defaults to the full image height.
  * @return {undefined}
  */
-CanvasRenderingContext2D.prototype.drawImage = function(
+BaseRenderingContext2D.prototype.drawImage = function(
     image, dx, dy, opt_dw, opt_dh, opt_sx, opt_sy, opt_sw, opt_sh) {};
 
 /**
  * @param {number} sw
  * @param {number} sh
- * @return {ImageData}
+ * @return {!ImageData}
+ * @throws {Error}
  * @nosideeffects
  */
-CanvasRenderingContext2D.prototype.createImageData = function(sw, sh) {};
+BaseRenderingContext2D.prototype.createImageData = function(sw, sh) {};
 
 /**
  * @param {number} sx
  * @param {number} sy
  * @param {number} sw
  * @param {number} sh
- * @return {ImageData}
+ * @return {!ImageData}
  * @throws {Error}
  */
-CanvasRenderingContext2D.prototype.getImageData = function(sx, sy, sw, sh) {};
+BaseRenderingContext2D.prototype.getImageData = function(sx, sy, sw, sh) {};
 
 /**
  * @param {ImageData} imagedata
@@ -503,7 +772,7 @@ CanvasRenderingContext2D.prototype.getImageData = function(sx, sy, sw, sh) {};
  * @param {number=} opt_dirtyHeight
  * @return {undefined}
  */
-CanvasRenderingContext2D.prototype.putImageData = function(imagedata, dx, dy,
+BaseRenderingContext2D.prototype.putImageData = function(imagedata, dx, dy,
     opt_dirtyX, opt_dirtyY, opt_dirtyWidth, opt_dirtyHeight) {};
 
 /**
@@ -515,8 +784,10 @@ CanvasRenderingContext2D.prototype.putImageData = function(imagedata, dx, dy,
  * @param {number=} opt_e
  * @see http://developer.apple.com/library/safari/#documentation/appleapplications/reference/WebKitDOMRef/CanvasRenderingContext2D_idl/Classes/CanvasRenderingContext2D/index.html
  * @return {undefined}
+ * @deprecated
  */
-CanvasRenderingContext2D.prototype.setFillColor;
+BaseRenderingContext2D.prototype.setFillColor = function(
+    opt_a, opt_b, opt_c, opt_d, opt_e) {};
 
 /**
  * Note: WebKit only
@@ -527,81 +798,108 @@ CanvasRenderingContext2D.prototype.setFillColor;
  * @param {number=} opt_e
  * @see http://developer.apple.com/library/safari/#documentation/appleapplications/reference/WebKitDOMRef/CanvasRenderingContext2D_idl/Classes/CanvasRenderingContext2D/index.html
  * @return {undefined}
+ * @deprecated
  */
-CanvasRenderingContext2D.prototype.setStrokeColor;
+BaseRenderingContext2D.prototype.setStrokeColor = function(
+    opt_a, opt_b, opt_c, opt_d, opt_e) {};
 
 /**
- * @return {Array<number>}
+ * @return {!Array<number>}
+ * @override
  */
-CanvasRenderingContext2D.prototype.getLineDash;
+BaseRenderingContext2D.prototype.getLineDash = function() {};
 
 /**
  * @param {Array<number>} segments
  * @return {undefined}
+ * @override
  */
-CanvasRenderingContext2D.prototype.setLineDash;
+BaseRenderingContext2D.prototype.setLineDash = function(segments) {};
 
 /** @type {string} */
-CanvasRenderingContext2D.prototype.fillColor;
+BaseRenderingContext2D.prototype.fillColor;
 
 /**
  * @type {string|!CanvasGradient|!CanvasPattern}
  * @see https://html.spec.whatwg.org/multipage/scripting.html#fill-and-stroke-styles:dom-context-2d-fillstyle
  * @implicitCast
  */
-CanvasRenderingContext2D.prototype.fillStyle;
+BaseRenderingContext2D.prototype.fillStyle;
 
 /** @type {string} */
-CanvasRenderingContext2D.prototype.font;
+BaseRenderingContext2D.prototype.font;
 
 /** @type {number} */
-CanvasRenderingContext2D.prototype.globalAlpha;
+BaseRenderingContext2D.prototype.globalAlpha;
 
 /** @type {string} */
-CanvasRenderingContext2D.prototype.globalCompositeOperation;
+BaseRenderingContext2D.prototype.globalCompositeOperation;
 
 /** @type {number} */
-CanvasRenderingContext2D.prototype.lineWidth;
+BaseRenderingContext2D.prototype.lineWidth;
 
 /** @type {string} */
-CanvasRenderingContext2D.prototype.lineCap;
+BaseRenderingContext2D.prototype.lineCap;
 
 /** @type {string} */
-CanvasRenderingContext2D.prototype.lineJoin;
+BaseRenderingContext2D.prototype.lineJoin;
 
 /** @type {number} */
-CanvasRenderingContext2D.prototype.miterLimit;
+BaseRenderingContext2D.prototype.miterLimit;
 
 /** @type {number} */
-CanvasRenderingContext2D.prototype.shadowBlur;
+BaseRenderingContext2D.prototype.shadowBlur;
 
 /** @type {string} */
-CanvasRenderingContext2D.prototype.shadowColor;
+BaseRenderingContext2D.prototype.shadowColor;
 
 /** @type {number} */
-CanvasRenderingContext2D.prototype.shadowOffsetX;
+BaseRenderingContext2D.prototype.shadowOffsetX;
 
 /** @type {number} */
-CanvasRenderingContext2D.prototype.shadowOffsetY;
+BaseRenderingContext2D.prototype.shadowOffsetY;
+
+/** @type {boolean} */
+BaseRenderingContext2D.prototype.imageSmoothingEnabled;
 
 /**
  * @type {string|!CanvasGradient|!CanvasPattern}
  * @see https://html.spec.whatwg.org/multipage/scripting.html#fill-and-stroke-styles:dom-context-2d-strokestyle
  * @implicitCast
  */
-CanvasRenderingContext2D.prototype.strokeStyle;
+BaseRenderingContext2D.prototype.strokeStyle;
 
 /** @type {string} */
-CanvasRenderingContext2D.prototype.strokeColor;
+BaseRenderingContext2D.prototype.strokeColor;
 
 /** @type {string} */
-CanvasRenderingContext2D.prototype.textAlign;
+BaseRenderingContext2D.prototype.textAlign;
 
 /** @type {string} */
-CanvasRenderingContext2D.prototype.textBaseline;
+BaseRenderingContext2D.prototype.textBaseline;
 
 /** @type {number} */
-CanvasRenderingContext2D.prototype.lineDashOffset;
+BaseRenderingContext2D.prototype.lineDashOffset;
+
+/**
+ * @constructor
+ * @extends {BaseRenderingContext2D}
+ * @see http://www.w3.org/TR/2dcontext/#canvasrenderingcontext2d
+ */
+function CanvasRenderingContext2D() {}
+
+/** @const {!HTMLCanvasElement} */
+CanvasRenderingContext2D.prototype.canvas;
+
+/**
+ * @constructor
+ * @extends {BaseRenderingContext2D}
+ * @see http://www.w3.org/TR/2dcontext/#canvasrenderingcontext2d
+ */
+function OffscreenCanvasRenderingContext2D() {}
+
+/** @const {!OffscreenCanvas} */
+OffscreenCanvasRenderingContext2D.prototype.canvas;
 
 /**
  * @constructor
@@ -625,11 +923,23 @@ function CanvasPattern() {}
  */
 function TextMetrics() {}
 
-/** @type {number} */
+/** @const {number} */
 TextMetrics.prototype.width;
 
+/** @const {number|undefined} */
+TextMetrics.prototype.actualBoundingBoxAscent;
+
+/** @const {number|undefined} */
+TextMetrics.prototype.actualBoundingBoxDescent;
+
+/** @const {number|undefined} */
+TextMetrics.prototype.actualBoundingBoxLeft;
+
+/** @const {number|undefined} */
+TextMetrics.prototype.actualBoundingBoxRight;
+
 /**
- * @param {Uint8ClampedArray|number} dataOrWidth In the first form, this is the
+ * @param {!Uint8ClampedArray|number} dataOrWidth In the first form, this is the
  *     array of pixel data.  In the second form, this is the image width.
  * @param {number} widthOrHeight In the first form, this is the image width.  In
  *     the second form, this is the image height.
@@ -640,15 +950,71 @@ TextMetrics.prototype.width;
  */
 function ImageData(dataOrWidth, widthOrHeight, opt_height) {}
 
-/** @type {Uint8ClampedArray} */
+/** @const {!Uint8ClampedArray} */
 ImageData.prototype.data;
 
-/** @type {number} */
+/** @const {number} */
 ImageData.prototype.width;
 
-/** @type {number} */
+/** @const {number} */
 ImageData.prototype.height;
 
+/**
+ * @see https://www.w3.org/TR/html51/webappapis.html#webappapis-images
+ * @interface
+ */
+function ImageBitmap() {}
+
+/**
+ * @const {number}
+ */
+ImageBitmap.prototype.width;
+
+/**
+ * @const {number}
+ */
+ImageBitmap.prototype.height;
+
+/**
+ * Releases ImageBitmap's underlying bitmap data.
+ * @return {undefined}
+ * @see https://html.spec.whatwg.org/multipage/imagebitmap-and-animations.html#images-2
+ */
+ImageBitmap.prototype.close = function() {};
+
+/**
+ * @typedef {!CanvasImageSource | !Blob | !ImageData}
+ * @see https://html.spec.whatwg.org/multipage/imagebitmap-and-animations.html#imagebitmapsource
+ */
+var ImageBitmapSource;
+
+/**
+ * @typedef {{
+ *   imageOrientation: (string|undefined),
+ *   premultiplyAlpha: (string|undefined),
+ *   colorSpaceConversion: (string|undefined),
+ *   resizeWidth: (number|undefined),
+ *   resizeHeight: (number|undefined),
+ *   resizeQuality: (string|undefined)
+ * }}
+ * @see https://html.spec.whatwg.org/multipage/imagebitmap-and-animations.html#images-2
+ */
+var ImageBitmapOptions;
+
+/**
+ * @param {!ImageBitmapSource} image
+ * @param {(number|!ImageBitmapOptions)=} sxOrOptions
+ * @param {number=} sy
+ * @param {number=} sw
+ * @param {number=} sh
+ * @param {!ImageBitmapOptions=} options
+ * @return {!Promise<!ImageBitmap>}
+ * @see https://html.spec.whatwg.org/multipage/imagebitmap-and-animations.html#dom-createimagebitmap
+ * @see https://html.spec.whatwg.org/multipage/webappapis.html#windoworworkerglobalscope-mixin
+ */
+function createImageBitmap(image, sxOrOptions, sy, sw, sh, options) {}
+
+
 /**
  * @constructor
  */
@@ -778,7 +1144,7 @@ SQLResultSet.prototype.insertId;
 SQLResultSet.prototype.rowsAffected;
 
 /**
- * @type {SQLResultSetRowList}
+ * @type {!SQLResultSetRowList}
  */
 SQLResultSet.prototype.rows;
 
@@ -807,7 +1173,7 @@ SQLResultSetRowList.prototype.item = function(index) {};
  * @param {string} description
  * @param {number} size
  * @param {(DatabaseCallback|function(Database))=} opt_callback
- * @return {Database}
+ * @return {!Database}
  */
 function openDatabase(name, version, description, size, opt_callback) {}
 
@@ -817,7 +1183,7 @@ function openDatabase(name, version, description, size, opt_callback) {}
  * @param {string} description
  * @param {number} size
  * @param {(DatabaseCallback|function(Database))=} opt_callback
- * @return {Database}
+ * @return {!Database}
  */
 Window.prototype.openDatabase =
     function(name, version, description, size, opt_callback) {};
@@ -846,6 +1212,25 @@ HTMLImageElement.prototype.naturalHeight;
  */
 HTMLImageElement.prototype.crossOrigin;
 
+/**
+ * @type {string}
+ * @see https://html.spec.whatwg.org/multipage/embedded-content.html#dom-img-currentsrc
+ */
+HTMLImageElement.prototype.currentSrc;
+
+/**
+ * @type {string}
+ * @see https://html.spec.whatwg.org/multipage/images.html#image-decoding-hint
+ */
+HTMLImageElement.prototype.decoding;
+
+/**
+ * @return {!Promise<undefined>}
+ * @see https://html.spec.whatwg.org/multipage/embedded-content.html#dom-img-decode
+ */
+HTMLImageElement.prototype.decode;
+
+
 /**
  * This is a superposition of the Window and Worker postMessage methods.
  * @param {*} message
@@ -857,6 +1242,15 @@ HTMLImageElement.prototype.crossOrigin;
 function postMessage(message, opt_targetOriginOrTransfer,
     opt_targetOriginOrPortsOrTransfer) {}
 
+/**
+ * @param {*} message
+ * @param {string=} targetOrigin
+ * @param {(!Array<!Transferable>)=} transfer
+ * @return {void}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/Window/postMessage
+ */
+Window.prototype.postMessage = function(message, targetOrigin, transfer) {};
+
 /**
  * The postMessage method (as implemented in Opera).
  * @param {string} message
@@ -871,240 +1265,226 @@ Document.prototype.postMessage = function(message) {};
 Document.prototype.head;
 
 /**
- * @see https://developer.apple.com/webapps/docs/documentation/AppleApplications/Reference/SafariJSRef/DOMApplicationCache/DOMApplicationCache.html
- * @constructor
- * @implements {EventTarget}
+ * @type {string}
+ * @see https://html.spec.whatwg.org/multipage/dom.html#current-document-readiness
  */
-function DOMApplicationCache() {}
+Document.prototype.readyState;
 
 /**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
+ * @see https://html.spec.whatwg.org/#application-cache-api
+ * @constructor
+ * @implements {EventTarget}
  */
-DOMApplicationCache.prototype.addEventListener = function(
-    type, listener, opt_useCapture) {};
+function ApplicationCache() {}
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-DOMApplicationCache.prototype.removeEventListener = function(
-    type, listener, opt_useCapture) {};
+/** @override */
+ApplicationCache.prototype.addEventListener = function(
+    type, listener, opt_options) {};
+
+/** @override */
+ApplicationCache.prototype.removeEventListener = function(
+    type, listener, opt_options) {};
+
+/** @override */
+ApplicationCache.prototype.dispatchEvent = function(evt) {};
 
 /**
- * @override
- * @return {boolean}
+ * The object isn't associated with an application cache. This can occur if the
+ * update process fails and there is no previous cache to revert to, or if there
+ * is no manifest file.
+ * @const {number}
  */
-DOMApplicationCache.prototype.dispatchEvent = function(evt) {};
+ApplicationCache.prototype.UNCACHED;
 
 /**
  * The object isn't associated with an application cache. This can occur if the
  * update process fails and there is no previous cache to revert to, or if there
  * is no manifest file.
- * @type {number}
+ * @const {number}
  */
-DOMApplicationCache.prototype.UNCACHED = 0;
+ApplicationCache.UNCACHED;
 
 /**
  * The cache is idle.
- * @type {number}
+ * @const {number}
+ */
+ApplicationCache.prototype.IDLE;
+
+/**
+ * The cache is idle.
+ * @const {number}
  */
-DOMApplicationCache.prototype.IDLE = 1;
+ApplicationCache.IDLE;
 
 /**
  * The update has started but the resources are not downloaded yet - for
  * example, this can happen when the manifest file is fetched.
- * @type {number}
+ * @const {number}
  */
-DOMApplicationCache.prototype.CHECKING = 2;
+ApplicationCache.prototype.CHECKING;
+
+/**
+ * The update has started but the resources are not downloaded yet - for
+ * example, this can happen when the manifest file is fetched.
+ * @const {number}
+ */
+ApplicationCache.CHECKING;
 
 /**
  * The resources are being downloaded into the cache.
- * @type {number}
+ * @const {number}
  */
-DOMApplicationCache.prototype.DOWNLOADING = 3;
+ApplicationCache.prototype.DOWNLOADING;
+
+/**
+ * The resources are being downloaded into the cache.
+ * @const {number}
+ */
+ApplicationCache.DOWNLOADING;
 
 /**
  * Resources have finished downloading and the new cache is ready to be used.
- * @type {number}
+ * @const {number}
+ */
+ApplicationCache.prototype.UPDATEREADY;
+
+/**
+ * Resources have finished downloading and the new cache is ready to be used.
+ * @const {number}
  */
-DOMApplicationCache.prototype.UPDATEREADY = 4;
+ApplicationCache.UPDATEREADY;
 
 /**
  * The cache is obsolete.
- * @type {number}
+ * @const {number}
  */
-DOMApplicationCache.prototype.OBSOLETE = 5;
+ApplicationCache.prototype.OBSOLETE;
+
+/**
+ * The cache is obsolete.
+ * @const {number}
+ */
+ApplicationCache.OBSOLETE;
 
 /**
  * The current status of the application cache.
  * @type {number}
  */
-DOMApplicationCache.prototype.status;
+ApplicationCache.prototype.status;
 
 /**
  * Sent when the update process finishes for the first time; that is, the first
  * time an application cache is saved.
- * @type {?function(!Event)}
+ * @type {?function(!Event): void}
  */
-DOMApplicationCache.prototype.oncached;
+ApplicationCache.prototype.oncached;
 
 /**
  * Sent when the cache update process begins.
- * @type {?function(!Event)}
+ * @type {?function(!Event): void}
  */
-DOMApplicationCache.prototype.onchecking;
+ApplicationCache.prototype.onchecking;
 
 /**
  * Sent when the update process begins downloading resources in the manifest
  * file.
- * @type {?function(!Event)}
+ * @type {?function(!Event): void}
  */
-DOMApplicationCache.prototype.ondownloading;
+ApplicationCache.prototype.ondownloading;
 
 /**
  * Sent when an error occurs.
- * @type {?function(!Event)}
+ * @type {?function(!Event): void}
  */
-DOMApplicationCache.prototype.onerror;
+ApplicationCache.prototype.onerror;
 
 /**
  * Sent when the update process finishes but the manifest file does not change.
- * @type {?function(!Event)}
+ * @type {?function(!Event): void}
  */
-DOMApplicationCache.prototype.onnoupdate;
+ApplicationCache.prototype.onnoupdate;
 
 /**
  * Sent when each resource in the manifest file begins to download.
- * @type {?function(!Event)}
+ * @type {?function(!Event): void}
  */
-DOMApplicationCache.prototype.onprogress;
+ApplicationCache.prototype.onprogress;
 
 /**
  * Sent when there is an existing application cache, the update process
  * finishes, and there is a new application cache ready for use.
- * @type {?function(!Event)}
+ * @type {?function(!Event): void}
  */
-DOMApplicationCache.prototype.onupdateready;
+ApplicationCache.prototype.onupdateready;
 
 /**
  * Replaces the active cache with the latest version.
  * @throws {DOMException}
  * @return {undefined}
  */
-DOMApplicationCache.prototype.swapCache = function() {};
+ApplicationCache.prototype.swapCache = function() {};
 
 /**
  * Manually triggers the update process.
  * @throws {DOMException}
  * @return {undefined}
  */
-DOMApplicationCache.prototype.update = function() {};
+ApplicationCache.prototype.update = function() {};
 
-/** @type {DOMApplicationCache} */
+/** @type {?ApplicationCache} */
 var applicationCache;
 
-/** @type {DOMApplicationCache} */
+/** @type {ApplicationCache} */
 Window.prototype.applicationCache;
 
 /**
  * @see https://developer.mozilla.org/En/DOM/Worker/Functions_available_to_workers
- * @param {...string} var_args
+ * @param {...!TrustedScriptURL|string} var_args
  * @return {undefined}
  */
 Window.prototype.importScripts = function(var_args) {};
 
 /**
- * @see https://developer.mozilla.org/En/DOM/Worker/Functions_available_to_workers
- * @param {...string} var_args
- * @return {undefined}
- */
-function importScripts(var_args) {}
-
-/**
- * @see http://dev.w3.org/html5/workers/
- * @constructor
- * @implements {EventTarget}
- */
-function WebWorker() {}
-
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-WebWorker.prototype.addEventListener = function(
-    type, listener, opt_useCapture) {};
-
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-WebWorker.prototype.removeEventListener = function(
-    type, listener, opt_useCapture) {};
-
-/**
- * @override
- * @return {boolean}
+ * Decodes a string of data which has been encoded using base-64 encoding.
+ *
+ * @param {string} encodedData
+ * @return {string}
+ * @nosideeffects
+ * @see https://html.spec.whatwg.org/multipage/webappapis.html#dom-atob
  */
-WebWorker.prototype.dispatchEvent = function(evt) {};
+function atob(encodedData) {}
 
 /**
- * Stops the worker process
- * @return {undefined}
+ * @param {string} stringToEncode
+ * @return {string}
+ * @nosideeffects
+ * @see https://html.spec.whatwg.org/multipage/webappapis.html#dom-btoa
  */
-WebWorker.prototype.terminate = function() {};
+function btoa(stringToEncode) {}
 
 /**
- * Posts a message to the worker thread.
- * @param {string} message
+ * @see https://developer.mozilla.org/En/DOM/Worker/Functions_available_to_workers
+ * @param {...!TrustedScriptURL|string} var_args
  * @return {undefined}
  */
-WebWorker.prototype.postMessage = function(message) {};
-
-/**
- * Sent when the worker thread posts a message to its creator.
- * @type {?function(!MessageEvent<*>)}
- */
-WebWorker.prototype.onmessage;
-
-/**
- * Sent when the worker thread encounters an error.
- * TODO(tbreisacher): Should this change to function(!ErrorEvent)?
- * @type {?function(!Event)}
- */
-WebWorker.prototype.onerror;
+function importScripts(var_args) {}
 
 /**
  * @see http://dev.w3.org/html5/workers/
+ * @param {!TrustedScriptURL|string} scriptURL
+ * @param {!WorkerOptions=} opt_options
  * @constructor
  * @implements {EventTarget}
  */
-function Worker(opt_arg0) {}
+function Worker(scriptURL, opt_options) {}
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-Worker.prototype.addEventListener = function(
-    type, listener, opt_useCapture) {};
+/** @override */
+Worker.prototype.addEventListener = function(type, listener, opt_options) {};
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-Worker.prototype.removeEventListener = function(
-    type, listener, opt_useCapture) {};
+/** @override */
+Worker.prototype.removeEventListener = function(type, listener, opt_options) {};
 
-/**
- * @override
- * @return {boolean}
- */
+/** @override */
 Worker.prototype.dispatchEvent = function(evt) {};
 
 /**
@@ -1131,47 +1511,62 @@ Worker.prototype.webkitPostMessage = function(message, opt_transfer) {};
 
 /**
  * Sent when the worker thread posts a message to its creator.
- * @type {?function(!MessageEvent<*>)}
+ * @type {?function(!MessageEvent<*>): void}
  */
 Worker.prototype.onmessage;
 
 /**
  * Sent when the worker thread encounters an error.
- * TODO(tbreisacher): Should this change to function(!ErrorEvent)?
- * @type {?function(!Event)}
+ * @type {?function(!ErrorEvent): void}
  */
 Worker.prototype.onerror;
 
 /**
  * @see http://dev.w3.org/html5/workers/
- * @param {string} scriptURL The URL of the script to run in the SharedWorker.
- * @param {string=} opt_name A name that can later be used to obtain a
- *     reference to the same SharedWorker.
- * @constructor
- * @implements {EventTarget}
+ * @record
  */
-function SharedWorker(scriptURL, opt_name) {}
+function WorkerOptions() {}
 
 /**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
+ * Defines a name for the new global environment of the worker, primarily for
+ * debugging purposes.
+ * @type {string|undefined}
  */
-SharedWorker.prototype.addEventListener = function(
-    type, listener, opt_useCapture) {};
+WorkerOptions.prototype.name;
 
 /**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
+ * 'classic' or 'module'. Default: 'classic'.
+ * Specifying 'module' ensures the worker environment supports JavaScript
+ * modules.
+ * @type {string|undefined}
  */
-SharedWorker.prototype.removeEventListener = function(
-    type, listener, opt_useCapture) {};
+WorkerOptions.prototype.type;
+
+// WorkerOptions.prototype.credentials is defined in fetchapi.js.
+// if type = 'module', it specifies how scriptURL is fetched.
 
 /**
- * @override
- * @return {boolean}
+ * @see http://dev.w3.org/html5/workers/
+ * @param {!TrustedScriptURL|string} scriptURL The URL of the script to run in
+ *     the SharedWorker.
+ * @param {(string|!WorkerOptions)=} options A name that can
+ *     later be used to obtain a reference to the same SharedWorker or a
+ *     WorkerOptions object which can be be used to specify how scriptURL is
+ *     fetched through the credentials option.
+ * @constructor
+ * @implements {EventTarget}
  */
+function SharedWorker(scriptURL, options) {}
+
+/** @override */
+SharedWorker.prototype.addEventListener = function(
+    type, listener, opt_options) {};
+
+/** @override */
+SharedWorker.prototype.removeEventListener = function(
+    type, listener, opt_options) {};
+
+/** @override */
 SharedWorker.prototype.dispatchEvent = function(evt) {};
 
 /**
@@ -1181,8 +1576,7 @@ SharedWorker.prototype.port;
 
 /**
  * Called on network errors for loading the initial script.
- * TODO(tbreisacher): Should this change to function(!ErrorEvent)?
- * @type {?function(!Event)}
+ * @type {?function(!ErrorEvent): void}
  */
 SharedWorker.prototype.onerror;
 
@@ -1227,10 +1621,10 @@ WorkerLocation.prototype.hash;
  */
 function WorkerGlobalScope() {}
 
-/** @type {WorkerGlobalScope} */
+/** @type {!WorkerGlobalScope} */
 WorkerGlobalScope.prototype.self;
 
-/** @type {WorkerLocation} */
+/** @type {!WorkerLocation} */
 WorkerGlobalScope.prototype.location;
 
 /**
@@ -1241,22 +1635,36 @@ WorkerGlobalScope.prototype.close = function() {};
 
 /**
  * Sent when the worker encounters an error.
- * @type {?function(!Event)}
+ * @type {?function(string, string, number, number, !Error): void}
  */
 WorkerGlobalScope.prototype.onerror;
 
 /**
  * Sent when the worker goes offline.
- * @type {?function(!Event)}
+ * @type {?function(!Event): void}
  */
 WorkerGlobalScope.prototype.onoffline;
 
 /**
  * Sent when the worker goes online.
- * @type {?function(!Event)}
+ * @type {?function(!Event): void}
  */
 WorkerGlobalScope.prototype.ononline;
 
+/** @type {!WorkerPerformance} */
+WorkerGlobalScope.prototype.performance;
+
+/** @type {!WorkerNavigator} */
+WorkerGlobalScope.prototype.navigator;
+
+/**
+ * Worker postMessage method.
+ * @param {*} message
+ * @param {(!Array<!Transferable>)=} transfer
+ * @return {void}
+ */
+WorkerGlobalScope.prototype.postMessage = function(message, transfer) {};
+
 /**
  * @see http://dev.w3.org/html5/workers/
  * @interface
@@ -1284,7 +1692,7 @@ DedicatedWorkerGlobalScope.prototype.webkitPostMessage =
 
 /**
  * Sent when the creator posts a message to this worker.
- * @type {?function(!MessageEvent<*>)}
+ * @type {?function(!MessageEvent<*>): void}
  */
 DedicatedWorkerGlobalScope.prototype.onmessage;
 
@@ -1304,9 +1712,38 @@ SharedWorkerGlobalScope.prototype.name;
  */
 SharedWorkerGlobalScope.prototype.onconnect;
 
+/** @type {!Array<string>|undefined} */
+HTMLElement.observedAttributes;
+
+/**
+ * @param {!Document} oldDocument
+ * @param {!Document} newDocument
+ */
+HTMLElement.prototype.adoptedCallback = function(oldDocument, newDocument) {};
+
+/**
+ * @param {!{mode: string}} options
+ * @return {!ShadowRoot}
+ */
+HTMLElement.prototype.attachShadow = function(options) {};
+
+/**
+ * @param {string} attributeName
+ * @param {?string} oldValue
+ * @param {?string} newValue
+ * @param {?string} namespace
+ */
+HTMLElement.prototype.attributeChangedCallback = function(attributeName, oldValue, newValue, namespace) {};
+
+/** @type {function()|undefined} */
+HTMLElement.prototype.connectedCallback;
+
 /** @type {Element} */
 HTMLElement.prototype.contextMenu;
 
+/** @type {function()|undefined} */
+HTMLElement.prototype.disconnectedCallback;
+
 /** @type {boolean} */
 HTMLElement.prototype.draggable;
 
@@ -1315,20 +1752,10 @@ HTMLElement.prototype.draggable;
  * interface isn't currently defined and no known browsers implement this
  * feature, just define the property for now.
  *
- * @const
- * @type {Object}
+ * @const {Object}
  */
 HTMLElement.prototype.dropzone;
 
-/**
- * @see http://www.w3.org/TR/html5/dom.html#dom-getelementsbyclassname
- * @param {string} classNames
- * @return {!NodeList<!Element>}
- * @nosideeffects
- */
-HTMLElement.prototype.getElementsByClassName = function(classNames) {};
-// NOTE: Document.prototype.getElementsByClassName is in gecko_dom.js
-
 /** @type {boolean} */
 HTMLElement.prototype.hidden;
 
@@ -1346,7 +1773,7 @@ var GetRootNodeOptions;
 /**
  * @see https://dom.spec.whatwg.org/#dom-node-getrootnode
  * @param {GetRootNodeOptions=} opt_options
- * @return {?Node}
+ * @return {!Node}
  */
 Node.prototype.getRootNode = function(opt_options) {};
 
@@ -1392,6 +1819,13 @@ HTMLElement.prototype.attachedCallback;
  */
 HTMLElement.prototype.detachedCallback;
 
+/**
+ * Cryptographic nonce used by Content Security Policy.
+ * @see https://html.spec.whatwg.org/multipage/dom.html#elements-in-the-dom:noncedelement
+ * @type {?string}
+ */
+HTMLElement.prototype.nonce;
+
 /** @type {string} */
 HTMLAnchorElement.prototype.download;
 
@@ -1423,6 +1857,9 @@ HTMLAnchorElement.prototype.port;
 /** @type {string} */
 HTMLAnchorElement.prototype.protocol;
 
+/** @type {!DOMTokenList} */
+HTMLAnchorElement.prototype.relList;
+
 /** @type {string} */
 HTMLAnchorElement.prototype.search;
 
@@ -1437,16 +1874,29 @@ HTMLAreaElement.prototype.ping;
 
 /**
  * @type {string}
+ * @implicitCast
  * @see http://www.w3.org/TR/html-markup/iframe.html#iframe.attrs.srcdoc
  */
 HTMLIFrameElement.prototype.srcdoc;
 
 /**
- * @type {?string}
+ * @type {?DOMTokenList}
  * @see http://www.w3.org/TR/2012/WD-html5-20121025/the-iframe-element.html#attr-iframe-sandbox
  */
 HTMLIFrameElement.prototype.sandbox;
 
+/**
+ * @type {string}
+ * @see https://html.spec.whatwg.org/multipage/iframe-embed-object.html#attr-iframe-allow
+ */
+HTMLIFrameElement.prototype.allow;
+
+/**
+ * @type {Window}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/HTMLIFrameElement/contentWindow
+ */
+HTMLIFrameElement.prototype.contentWindow;
+
 /** @type {string} */
 HTMLInputElement.prototype.autocomplete;
 
@@ -1518,39 +1968,117 @@ HTMLInputElement.prototype.stepUp = function(opt_n) {};
 function HTMLMediaElement() {}
 
 /**
- * @type {number}
- * @const
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-network_empty
+ * @const {number}
  */
-HTMLMediaElement.HAVE_NOTHING;  // = 0
+HTMLMediaElement.NETWORK_EMPTY;
 
 /**
- * @type {number}
- * @const
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-network_empty
+ * @const {number}
  */
-HTMLMediaElement.HAVE_METADATA;  // = 1
+HTMLMediaElement.prototype.NETWORK_EMPTY;
 
 /**
- * @type {number}
- * @const
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-network_idle
+ * @const {number}
  */
-HTMLMediaElement.HAVE_CURRENT_DATA;  // = 2
+HTMLMediaElement.NETWORK_IDLE;
 
 /**
- * @type {number}
- * @const
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-network_idle
+ * @const {number}
  */
-HTMLMediaElement.HAVE_FUTURE_DATA;  // = 3
+HTMLMediaElement.prototype.NETWORK_IDLE;
 
 /**
- * @type {number}
- * @const
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-network_loading
+ * @const {number}
+ */
+HTMLMediaElement.NETWORK_LOADING;
+
+/**
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-network_loading
+ * @const {number}
+ */
+HTMLMediaElement.prototype.NETWORK_LOADING;
+
+/**
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-network_no_source
+ * @const {number}
+ */
+HTMLMediaElement.NETWORK_NO_SOURCE;
+
+/**
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-network_no_source
+ * @const {number}
+ */
+HTMLMediaElement.prototype.NETWORK_NO_SOURCE;
+
+/**
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-have_nothing
+ * @const {number}
+ */
+HTMLMediaElement.HAVE_NOTHING;
+
+/**
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-have_nothing
+ * @const {number}
  */
-HTMLMediaElement.HAVE_ENOUGH_DATA;  // = 4
+HTMLMediaElement.prototype.HAVE_NOTHING;
+
+/**
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-have_metadata
+ * @const {number}
+ */
+HTMLMediaElement.HAVE_METADATA;
+
+/**
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-have_metadata
+ * @const {number}
+ */
+HTMLMediaElement.prototype.HAVE_METADATA;
+
+/**
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-have_current_data
+ * @const {number}
+ */
+HTMLMediaElement.HAVE_CURRENT_DATA;
+
+/**
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-have_current_data
+ * @const {number}
+ */
+HTMLMediaElement.prototype.HAVE_CURRENT_DATA;
+
+/**
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-have_future_data
+ * @const {number}
+ */
+HTMLMediaElement.HAVE_FUTURE_DATA;
+
+/**
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-have_future_data
+ * @const {number}
+ */
+HTMLMediaElement.prototype.HAVE_FUTURE_DATA;
+
+/**
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-have_enough_data
+ * @const {number}
+ */
+HTMLMediaElement.HAVE_ENOUGH_DATA;
+
+/**
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-have_enough_data
+ * @const {number}
+ */
+HTMLMediaElement.prototype.HAVE_ENOUGH_DATA;
 
 /** @type {MediaError} */
 HTMLMediaElement.prototype.error;
 
-/** @type {string} */
+/** @type {string} @implicitCast */
 HTMLMediaElement.prototype.src;
 
 /** @type {string} */
@@ -1562,9 +2090,12 @@ HTMLMediaElement.prototype.networkState;
 /** @type {boolean} */
 HTMLMediaElement.prototype.autobuffer;
 
-/** @type {TimeRanges} */
+/** @type {!TimeRanges} */
 HTMLMediaElement.prototype.buffered;
 
+/** @type {?MediaStream} */
+HTMLMediaElement.prototype.srcObject;
+
 /**
  * Loads the media element.
  * @return {undefined}
@@ -1652,12 +2183,21 @@ HTMLImageElement.prototype.onload;
 /** @type {?function(Event)} */
 HTMLImageElement.prototype.onerror;
 
+/** @type {string} */
+HTMLMediaElement.prototype.preload;
+
 /** @type {number} */
 HTMLMediaElement.prototype.readyState;
 
 /** @type {boolean} */
 HTMLMediaElement.prototype.seeking;
 
+/**
+ * @type {string}
+ * @see https://html.spec.whatwg.org/multipage/media.html#dom-media-crossorigin
+ */
+HTMLMediaElement.prototype.crossOrigin;
+
 /**
  * The current time, in seconds.
  * @type {number}
@@ -1702,7 +2242,9 @@ HTMLMediaElement.prototype.loop;
 
 /**
  * Starts playing the media.
- * @return {undefined}
+ * @return {?Promise<undefined>} This is a *nullable* Promise on purpose unlike
+ *     the HTML5 spec because supported older browsers (incl. Smart TVs) don't
+ *     return a Promise.
  */
 HTMLMediaElement.prototype.play = function() {};
 
@@ -1729,14 +2271,64 @@ HTMLMediaElement.prototype.muted;
  * @param {string} kind Kind of the text track.
  * @param {string=} opt_label Label of the text track.
  * @param {string=} opt_language Language of the text track.
- * @return {TextTrack} TextTrack object added to the media element.
+ * @return {!TextTrack} TextTrack object added to the media element.
  */
 HTMLMediaElement.prototype.addTextTrack =
     function(kind, opt_label, opt_language) {};
 
-/** @type {TextTrackList} */
+/** @type {!TextTrackList} */
 HTMLMediaElement.prototype.textTracks;
 
+/**
+ * The ID of the audio device through which output is being delivered, or an
+ * empty string if using the default device.
+ *
+ * Implemented as a draft spec in Chrome 49+.
+ *
+ * @see https://w3c.github.io/mediacapture-output/#htmlmediaelement-extensions
+ * @type {string}
+ */
+HTMLMediaElement.prototype.sinkId;
+
+/**
+ * Sets the audio device through which output should be delivered.
+ *
+ * Implemented as a draft spec in Chrome 49+.
+ *
+ * @param {string} sinkId The ID of the audio output device, or empty string
+ * for default device.
+ *
+ * @see https://w3c.github.io/mediacapture-output/#htmlmediaelement-extensions
+ * @return {!Promise<void>}
+ */
+HTMLMediaElement.prototype.setSinkId = function(sinkId) {};
+
+
+/**
+ * Produces a real-time capture of the media that is rendered to the media
+ * element.
+ * @return {!MediaStream}
+ * @see https://w3c.github.io/mediacapture-fromelement/#html-media-element-media-capture-extensions
+ */
+HTMLMediaElement.prototype.captureStream = function() {};
+
+/**
+ * The Firefox flavor of captureStream.
+ * @return {!MediaStream}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/HTMLMediaElement/captureStream#Browser_compatibility
+ */
+HTMLMediaElement.prototype.mozCaptureStream = function() {};
+
+/**
+ * @constructor
+ * @extends {HTMLElement}
+ * @see https://html.spec.whatwg.org/multipage/dom.html#htmlunknownelement
+ * @see https://html.spec.whatwg.org/multipage/scripting.html#customized-built-in-element-restrictions
+ * @see https://w3c.github.io/webcomponents/spec/custom/#custom-elements-api
+ */
+function HTMLUnknownElement() {}
+
+
 
 /**
  * @see http://www.w3.org/TR/shadow-dom/
@@ -1748,6 +2340,7 @@ Text.prototype.getDestinationInsertionPoints = function() {};
 /**
  * @see http://www.whatwg.org/specs/web-apps/current-work/multipage/the-video-element.html#texttracklist
  * @constructor
+ * @implements {EventTarget}
  * @implements {IArrayLike<!TextTrack>}
  */
 function TextTrackList() {}
@@ -1761,6 +2354,16 @@ TextTrackList.prototype.length;
  */
 TextTrackList.prototype.getTrackById = function(id) {};
 
+/** @override */
+TextTrackList.prototype.addEventListener = function(
+    type, listener, opt_useCapture) {};
+
+/** @override */
+TextTrackList.prototype.dispatchEvent = function(evt) {};
+
+/** @override */
+TextTrackList.prototype.removeEventListener = function(
+    type, listener, opt_options) {};
 
 /**
  * @see http://www.whatwg.org/specs/web-apps/current-work/multipage/the-video-element.html#texttrack
@@ -1796,24 +2399,16 @@ TextTrack.prototype.cues;
  */
 TextTrack.prototype.mode;
 
-/**
- * @override
- * @return {undefined}
- */
-TextTrack.prototype.addEventListener = function(type, listener, useCapture) {};
+/** @override */
+TextTrack.prototype.addEventListener = function(
+    type, listener, opt_useCapture) {};
 
-/**
- * @override
- * @return {boolean}
- */
+/** @override */
 TextTrack.prototype.dispatchEvent = function(evt) {};
 
-/**
- * @override
- * @return {undefined}
- */
-TextTrack.prototype.removeEventListener = function(type, listener, useCapture)
-    {};
+/** @override */
+TextTrack.prototype.removeEventListener = function(
+    type, listener, opt_options) {};
 
 
 
@@ -1857,13 +2452,97 @@ TextTrackCue.prototype.endTime;
 TextTrackCue.prototype.text;
 
 
+
+/**
+ * @see https://w3c.github.io/webvtt/#vttregion
+ * @constructor
+ */
+function VTTRegion() {}
+
+/** @type {string} */
+VTTRegion.prototype.id;
+
+/** @type {number} */
+VTTRegion.prototype.width;
+
+/** @type {number} */
+VTTRegion.prototype.lines;
+
+/** @type {number} */
+VTTRegion.prototype.regionAnchorX;
+
+/** @type {number} */
+VTTRegion.prototype.regionAnchorY;
+
+/** @type {number} */
+VTTRegion.prototype.viewportAnchorX;
+
+/** @type {number} */
+VTTRegion.prototype.viewportAnchorY;
+
+/**
+ * @see https://w3c.github.io/webvtt/#enumdef-scrollsetting
+ * @type {string}
+ */
+VTTRegion.prototype.scroll;
+
+
+
 /**
  * @see http://dev.w3.org/html5/webvtt/#the-vttcue-interface
  * @constructor
  * @extends {TextTrackCue}
+ * @param {number} startTime
+ * @param {number} endTime
+ * @param {string} text
  */
 function VTTCue(startTime, endTime, text) {}
 
+/** @type {?VTTRegion} */
+VTTCue.prototype.region;
+
+/**
+ * @see https://w3c.github.io/webvtt/#enumdef-directionsetting
+ * @type {string}
+ */
+VTTCue.prototype.vertical;
+
+/** @type {boolean} */
+VTTCue.prototype.snapToLines;
+
+/** @type {(number|string)} */
+VTTCue.prototype.line;
+
+/**
+ * @see https://w3c.github.io/webvtt/#enumdef-linealignsetting
+ * @type {string}
+ */
+VTTCue.prototype.lineAlign;
+
+/** @type {(number|string)} */
+VTTCue.prototype.position;
+
+/**
+ * @see https://w3c.github.io/webvtt/#enumdef-positionalignsetting
+ * @type {string}
+ */
+VTTCue.prototype.positionAlign;
+
+/** @type {number} */
+VTTCue.prototype.size;
+
+/**
+ * @see https://w3c.github.io/webvtt/#enumdef-alignsetting
+ * @type {string}
+ */
+VTTCue.prototype.align;
+
+/** @type {string} */
+VTTCue.prototype.text;
+
+/** @return {!DocumentFragment} */
+VTTCue.prototype.getCueAsHTML = function() {};
+
 
 /**
  * @constructor
@@ -1875,7 +2554,7 @@ function HTMLAudioElement() {}
  * @constructor
  * @extends {HTMLMediaElement}
  * The webkit-prefixed attributes are defined in
- * https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit/Source/core/html/HTMLVideoElement.idl
+ * https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/html/media/HTMLMediaElement.idl
  */
 function HTMLVideoElement() {}
 
@@ -1936,7 +2615,8 @@ HTMLVideoElement.prototype.webkitDroppedFrameCount;
  *    totalVideoFrames: number,
  *    droppedVideoFrames: number,
  *    corruptedVideoFrames: number,
- *    totalFrameDelay: number
+ *    totalFrameDelay: number,
+ *    displayCompositedVideoFrames: (number|undefined)
  * }}
  */
 var VideoPlaybackQuality;
@@ -1948,38 +2628,140 @@ var VideoPlaybackQuality;
 HTMLVideoElement.prototype.getVideoPlaybackQuality = function() {};
 
 
+/**
+ * The metadata provided by the callback given to
+ * HTMLVideoElement.requestVideoFrameCallback().
+ *
+ * See https://wicg.github.io/video-rvfc/#video-frame-metadata
+ *
+ * @record
+ */
+function VideoFrameMetadata() {};
+
+/**
+ * The time at which the user agent submitted the frame for composition.
+ * @const {number}
+ */
+VideoFrameMetadata.prototype.presentationTime;
+
+/**
+ * The time at which the user agent expects the frame to be visible.
+ * @const {number}
+ */
+VideoFrameMetadata.prototype.expectedDisplayTime;
+
+/**
+ * The width of the video frame, in media pixels.
+ * @const {number}
+ */
+VideoFrameMetadata.prototype.width;
+
+/**
+ * The height of the video frame, in media pixels.
+ * @const {number}
+ */
+VideoFrameMetadata.prototype.height;
+
+/**
+ * The media presentation timestamp (PTS) in seconds of the frame presented
+ * (e.g. its timestamp on the video.currentTime timeline).
+ * @const {number}
+ */
+VideoFrameMetadata.prototype.mediaTime;
+
+/**
+ * A count of the number of frames submitted for composition.
+ * @const {number}
+ */
+VideoFrameMetadata.prototype.presentedFrames;
+
+/**
+ * The elapsed duration in seconds from submission of the encoded packet with
+ * the same presentation timestamp (PTS) as this frame (e.g. same as the
+ * mediaTime) to the decoder until the decoded frame was ready for presentation.
+ * @const {number|undefined}
+ */
+VideoFrameMetadata.prototype.processingDuration;
+
+/**
+ * For video frames coming from either a local or remote source, this is the
+ * time at which the frame was captured by the camera.
+ * @const {number|undefined}
+ */
+VideoFrameMetadata.prototype.captureTime;
+
+/**
+ * For video frames coming from a remote source, this is the time the encoded
+ * frame was received by the platform, i.e., the time at which the last packet
+ * belonging to this frame was received over the network.
+ * @const {number|undefined}
+ */
+VideoFrameMetadata.prototype.receiveTime;
+
+/**
+ * The RTP timestamp associated with this video frame.
+ * @const {number|undefined}
+ */
+VideoFrameMetadata.prototype.rtpTimestamp;
+
+/**
+ * @typedef {function(number,  ?VideoFrameMetadata): undefined}
+ * @see https://wicg.github.io/video-rvfc/#dom-htmlvideoelement-requestvideoframecallback
+ */
+var VideoFrameRequestCallback;
+
+/**
+ * Registers a callback to be fired the next time a frame is presented to the
+ * compositor.
+ * @param {!VideoFrameRequestCallback} callback
+ * @return {number}
+ */
+HTMLVideoElement.prototype.requestVideoFrameCallback = function(callback) {};
+
+/**
+ * Cancels an existing video frame request callback given its handle.
+ * @param {number} handle
+ * @return {undefined}
+ */
+HTMLVideoElement.prototype.cancelVideoFrameCallback = function(handle) {};
+
+
 /**
  * @constructor
+ * @see https://html.spec.whatwg.org/multipage/media.html#error-codes
  */
 function MediaError() {}
 
 /** @type {number} */
 MediaError.prototype.code;
 
+/** @type {string} */
+MediaError.prototype.message;
+
 /**
  * The fetching process for the media resource was aborted by the user agent at
  * the user's request.
- * @type {number}
+ * @const {number}
  */
 MediaError.MEDIA_ERR_ABORTED;
 
 /**
  * A network error of some description caused the user agent to stop fetching
  * the media resource, after the resource was established to be usable.
- * @type {number}
+ * @const {number}
  */
 MediaError.MEDIA_ERR_NETWORK;
 
 /**
  * An error of some description occurred while decoding the media resource,
  * after the resource was established to be usable.
- * @type {number}
+ * @const {number}
  */
 MediaError.MEDIA_ERR_DECODE;
 
 /**
  * The media resource indicated by the src attribute was not suitable.
- * @type {number}
+ * @const {number}
  */
 MediaError.MEDIA_ERR_SRC_NOT_SUPPORTED;
 
@@ -2011,26 +2793,15 @@ MessageChannel.prototype.port2;
  */
 function MessagePort() {}
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-MessagePort.prototype.addEventListener = function(
-    type, listener, opt_useCapture) {};
+/** @override */
+MessagePort.prototype.addEventListener = function(type, listener, opt_options) {
+};
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
+/** @override */
 MessagePort.prototype.removeEventListener = function(
-    type, listener, opt_useCapture) {};
+    type, listener, opt_options) {};
 
-/**
- * @override
- * @return {boolean}
- */
+/** @override */
 MessagePort.prototype.dispatchEvent = function(evt) {};
 
 
@@ -2058,20 +2829,51 @@ MessagePort.prototype.close = function() {};
 
 /**
  * TODO(blickly): Change this to MessageEvent<*> and add casts as needed
- * @type {?function(!MessageEvent<?>)}
+ * @type {?function(!MessageEvent<?>): void}
  */
 MessagePort.prototype.onmessage;
 
 // HTML5 MessageEvent class
 /**
- * @see http://dev.w3.org/html5/spec/comms.html#messageevent
+ * @typedef {Window|MessagePort|ServiceWorker}
+ * @see https://html.spec.whatwg.org/multipage/comms.html#messageeventsource
+ */
+var MessageEventSource;
+
+
+/**
+ * @record
+ * @extends {EventInit}
+ * @template T
+ * @see https://html.spec.whatwg.org/multipage/comms.html#messageeventinit
+ */
+function MessageEventInit() {}
+
+/** @type {T|undefined} */
+MessageEventInit.prototype.data;
+
+/** @type {(string|undefined)} */
+MessageEventInit.prototype.origin;
+
+/** @type {(string|undefined)} */
+MessageEventInit.prototype.lastEventId;
+
+/** @type {(?MessageEventSource|undefined)} */
+MessageEventInit.prototype.source;
+
+/** @type {(!Array<MessagePort>|undefined)} */
+MessageEventInit.prototype.ports;
+
+
+/**
+ * @see https://html.spec.whatwg.org/multipage/comms.html#messageevent
  * @constructor
  * @extends {Event}
- * @template T
  * @param {string} type
- * @param {Object=} init
+ * @param {MessageEventInit<T>=} opt_eventInitDict
+ * @template T
  */
-function MessageEvent(type, init) {}
+function MessageEvent(type, opt_eventInitDict) {}
 
 /**
  * The data payload of the message.
@@ -2101,7 +2903,7 @@ MessageEvent.prototype.source;
 /**
  * The Array of MessagePorts sent with the message, for cross-document
  * messaging and channel messaging.
- * @type {Array<MessagePort>}
+ * @type {!Array<MessagePort>}
  */
 MessageEvent.prototype.ports;
 
@@ -2109,13 +2911,13 @@ MessageEvent.prototype.ports;
  * Initializes the event in a manner analogous to the similarly-named methods in
  * the DOM Events interfaces.
  * @param {string} typeArg
- * @param {boolean} canBubbleArg
- * @param {boolean} cancelableArg
- * @param {T} dataArg
- * @param {string} originArg
- * @param {string} lastEventIdArg
- * @param {Window} sourceArg
- * @param {Array<MessagePort>} portsArg
+ * @param {boolean=} canBubbleArg
+ * @param {boolean=} cancelableArg
+ * @param {T=} dataArg
+ * @param {string=} originArg
+ * @param {string=} lastEventIdArg
+ * @param {?MessageEventSource=} sourceArg
+ * @param {!Array<MessagePort>=} portsArg
  * @return {undefined}
  */
 MessageEvent.prototype.initMessageEvent = function(typeArg, canBubbleArg,
@@ -2125,20 +2927,65 @@ MessageEvent.prototype.initMessageEvent = function(typeArg, canBubbleArg,
  * Initializes the event in a manner analogous to the similarly-named methods in
  * the DOM Events interfaces.
  * @param {string} namespaceURI
- * @param {string} typeArg
- * @param {boolean} canBubbleArg
- * @param {boolean} cancelableArg
- * @param {T} dataArg
- * @param {string} originArg
- * @param {string} lastEventIdArg
- * @param {Window} sourceArg
- * @param {Array<MessagePort>} portsArg
+ * @param {string=} typeArg
+ * @param {boolean=} canBubbleArg
+ * @param {boolean=} cancelableArg
+ * @param {T=} dataArg
+ * @param {string=} originArg
+ * @param {string=} lastEventIdArg
+ * @param {?MessageEventSource=} sourceArg
+ * @param {!Array<MessagePort>=} portsArg
  * @return {undefined}
  */
 MessageEvent.prototype.initMessageEventNS = function(namespaceURI, typeArg,
     canBubbleArg, cancelableArg, dataArg, originArg, lastEventIdArg, sourceArg,
     portsArg) {};
 
+/**
+ * @record
+ * @extends {EventInit}
+ * @see https://html.spec.whatwg.org/multipage/web-sockets.html#the-closeevent-interface
+ */
+function CloseEventInit() {}
+
+/**
+ * @type {undefined|boolean}
+ */
+CloseEventInit.prototype.wasClean;
+
+/**
+ * @type {undefined|number}
+ */
+CloseEventInit.prototype.code;
+
+/**
+ * @type {undefined|string}
+ */
+CloseEventInit.prototype.reason;
+
+/**
+ * @constructor
+ * @extends {Event}
+ * @param {string} type
+ * @param {!CloseEventInit=} opt_init
+ */
+var CloseEvent = function(type, opt_init) {};
+
+/**
+ * @type {boolean}
+ */
+CloseEvent.prototype.wasClean;
+
+/**
+ * @type {number}
+ */
+CloseEvent.prototype.code;
+
+/**
+ * @type {string}
+ */
+CloseEvent.prototype.reason;
+
 /**
  * HTML5 BroadcastChannel class.
  * @param {string} channelName
@@ -2154,25 +3001,25 @@ function BroadcastChannel(channelName) {}
  * listening to the same channel.
  * @param {*} message
  */
-BroadcastChannel.prototype.postMessage;
+BroadcastChannel.prototype.postMessage = function(message) {};
 
 /**
  * Closes the channel object, indicating it won't get any new messages, and
  * allowing it to be, eventually, garbage collected.
  * @return {void}
  */
-BroadcastChannel.prototype.close;
+BroadcastChannel.prototype.close = function() {};
 
 /** @override */
 BroadcastChannel.prototype.addEventListener = function(
-    type, listener, useCapture) {};
+    type, listener, opt_options) {};
 
 /** @override */
 BroadcastChannel.prototype.dispatchEvent = function(evt) {};
 
 /** @override */
 BroadcastChannel.prototype.removeEventListener = function(
-    type, listener, useCapture) {};
+    type, listener, opt_options) {};
 
 /**
  * An EventHandler property that specifies the function to execute when a
@@ -2190,15 +3037,10 @@ BroadcastChannel.prototype.name;
 /**
  * HTML5 DataTransfer class.
  *
- * We say that this extends ClipboardData, because Event.prototype.clipboardData
- * is a DataTransfer on WebKit but a ClipboardData on IE. The interfaces are so
- * similar that it's easier to merge them.
- *
  * @see http://www.w3.org/TR/2011/WD-html5-20110113/dnd.html
  * @see http://www.whatwg.org/specs/web-apps/current-work/multipage/dnd.html
  * @see http://developers.whatwg.org/dnd.html#datatransferitem
  * @constructor
- * @extends {ClipboardData}
  */
 function DataTransfer() {}
 
@@ -2208,15 +3050,14 @@ DataTransfer.prototype.dropEffect;
 /** @type {string} */
 DataTransfer.prototype.effectAllowed;
 
-/** @type {Array<string>} */
+/** @type {!Array<string>} */
 DataTransfer.prototype.types;
 
-/** @type {FileList} */
+/** @type {!FileList} */
 DataTransfer.prototype.files;
 
 /**
  * @param {string=} opt_format Format for which to remove data.
- * @override
  * @return {undefined}
  */
 DataTransfer.prototype.clearData = function(opt_format) {};
@@ -2224,7 +3065,6 @@ DataTransfer.prototype.clearData = function(opt_format) {};
 /**
  * @param {string} format Format for which to set data.
  * @param {string} data Data to add.
- * @override
  * @return {boolean}
  */
 DataTransfer.prototype.setData = function(format, data) {};
@@ -2232,7 +3072,6 @@ DataTransfer.prototype.setData = function(format, data) {};
 /**
  * @param {string} format Format for which to set data.
  * @return {string} Data for the given format.
- * @override
  */
 DataTransfer.prototype.getData = function(format) { return ''; };
 
@@ -2285,13 +3124,13 @@ WheelEventInit.prototype.deltaMode;
  */
 function WheelEvent(type, opt_eventInitDict) {}
 
-/** @type {number} */
+/** @const {number} */
 WheelEvent.DOM_DELTA_PIXEL;
 
-/** @type {number} */
+/** @const {number} */
 WheelEvent.DOM_DELTA_LINE;
 
-/** @type {number} */
+/** @const {number} */
 WheelEvent.DOM_DELTA_PAGE;
 
 /** @const {number} */
@@ -2334,14 +3173,6 @@ DataTransferItem.prototype.getAsString = function(callback) {};
  */
 DataTransferItem.prototype.getAsFile = function() { return null; };
 
-/**
- * @return {?Entry} The Entry corresponding to this item, or null. Note that
- * despite its name,this method only works in Chrome, and will eventually
- * be renamed to {@code getAsEntry}.
- * @nosideeffects
- */
-DataTransferItem.prototype.webkitGetAsEntry = function() { return null; };
-
 /**
  * HTML5 DataTransferItemList class. There are some discrepancies in the docs
  * on the whatwg.org site. When in doubt, these prototypes match what is
@@ -2432,6 +3263,7 @@ ProgressEventInit.prototype.total;
 
 /**
  * @constructor
+ * @template TARGET
  * @param {string} type
  * @param {ProgressEventInit=} opt_progressEventInitDict
  * @extends {Event}
@@ -2439,6 +3271,12 @@ ProgressEventInit.prototype.total;
  */
 function ProgressEvent(type, opt_progressEventInitDict) {}
 
+/**
+ * @override
+ * @type {TARGET}
+ */
+ProgressEvent.prototype.target;
+
 /** @type {number} */
 ProgressEvent.prototype.total;
 
@@ -2474,58 +3312,70 @@ TimeRanges.prototype.end = function(index) { return 0; };
 
 // HTML5 Web Socket class
 /**
- * @see http://dev.w3.org/html5/websockets/
+ * @see https://html.spec.whatwg.org/multipage/web-sockets.html
  * @constructor
  * @param {string} url
- * @param {string=} opt_protocol
+ * @param {(string|!Array<string>)=} opt_protocol
  * @implements {EventTarget}
  */
 function WebSocket(url, opt_protocol) {}
 
 /**
  * The connection has not yet been established.
- * @type {number}
+ * @const {number}
+ */
+WebSocket.CONNECTING;
+
+/**
+ * The connection has not yet been established.
+ * @const {number}
  */
-WebSocket.CONNECTING = 0;
+WebSocket.prototype.CONNECTING;
 
 /**
  * The WebSocket connection is established and communication is possible.
- * @type {number}
+ * @const {number}
  */
-WebSocket.OPEN = 1;
+WebSocket.OPEN;
 
 /**
- * The connection is going through the closing handshake, or the close() method has been invoked.
- * @type {number}
+ * The WebSocket connection is established and communication is possible.
+ * @const {number}
  */
-WebSocket.CLOSING = 2;
+WebSocket.prototype.OPEN;
 
 /**
- * The connection has been closed or could not be opened.
- * @type {number}
+ * The connection is going through the closing handshake, or the close() method has been invoked.
+ * @const {number}
  */
-WebSocket.CLOSED = 3;
+WebSocket.CLOSING;
 
 /**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
+ * The connection is going through the closing handshake, or the close() method has been invoked.
+ * @const {number}
  */
-WebSocket.prototype.addEventListener = function(
-    type, listener, opt_useCapture) {};
+WebSocket.prototype.CLOSING;
 
 /**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
+ * The connection has been closed or could not be opened.
+ * @const {number}
  */
-WebSocket.prototype.removeEventListener = function(
-    type, listener, opt_useCapture) {};
+WebSocket.CLOSED;
 
 /**
- * @override
- * @return {boolean}
+ * The connection has been closed or could not be opened.
+ * @const {number}
  */
+WebSocket.prototype.CLOSED;
+
+/** @override */
+WebSocket.prototype.addEventListener = function(type, listener, opt_options) {};
+
+/** @override */
+WebSocket.prototype.removeEventListener = function(
+    type, listener, opt_options) {};
+
+/** @override */
 WebSocket.prototype.dispatchEvent = function(evt) {};
 
 /**
@@ -2546,29 +3396,34 @@ WebSocket.prototype.readyState;
  */
 WebSocket.prototype.bufferedAmount;
 
+/**
+ * An event handler called on error event.
+ * @type {?function(!Event): void}
+ */
+WebSocket.prototype.onerror;
+
 /**
  * An event handler called on open event.
- * @type {?function(!Event)}
+ * @type {?function(!Event): void}
  */
 WebSocket.prototype.onopen;
 
 /**
  * An event handler called on message event.
- * TODO(blickly): Change this to MessageEvent<*> and add casts as needed
- * @type {?function(!MessageEvent<?>)}
+ * @type {?function(!MessageEvent<string|!ArrayBuffer|!Blob>): void}
  */
 WebSocket.prototype.onmessage;
 
 /**
  * An event handler called on close event.
- * @type {?function(!Event)}
+ * @type {?function(!CloseEvent): void}
  */
 WebSocket.prototype.onclose;
 
 /**
  * Transmits data using the connection.
- * @param {string|ArrayBuffer|ArrayBufferView} data
- * @return {boolean}
+ * @param {string|!ArrayBuffer|!ArrayBufferView|!Blob} data
+ * @return {void}
  */
 WebSocket.prototype.send = function(data) {};
 
@@ -2588,9 +3443,45 @@ WebSocket.prototype.binaryType;
 // HTML5 History
 /**
  * @constructor
+ * @see http://w3c.github.io/html/browsers.html#the-history-interface
  */
 function History() {}
 
+/**
+ * Goes back one step in the joint session history.
+ * If there is no previous page, does nothing.
+ *
+ * @see https://html.spec.whatwg.org/multipage/history.html#dom-history-back
+ *
+ * @return {undefined}
+ */
+History.prototype.back = function() {};
+
+/**
+ * Goes forward one step in the joint session history.
+ * If there is no next page, does nothing.
+ *
+ * @return {undefined}
+ */
+History.prototype.forward = function() {};
+
+/**
+ * The number of entries in the joint session history.
+ *
+ * @type {number}
+ */
+History.prototype.length;
+
+/**
+ * Goes back or forward the specified number of steps in the joint session
+ * history. A zero delta will reload the current page. If the delta is out of
+ * range, does nothing.
+ *
+ * @param {number} delta The number of entries to go back.
+ * @return {undefined}
+ */
+History.prototype.go = function(delta) {};
+
 /**
  * Pushes a new state into the session history.
  * @see http://www.w3.org/TR/html5/history.html#the-history-interface
@@ -2630,6 +3521,128 @@ History.prototype.state;
  */
 History.prototype.scrollRestoration;
 
+/**
+ * Add history property to Window.
+ *
+ * @type {!History}
+ */
+Window.prototype.history;
+
+/**
+ * @constructor
+ * @see https://html.spec.whatwg.org/multipage/history.html#the-location-interface
+ */
+function Location() {}
+
+/**
+ * Returns the Location object's URL. Can be set, to navigate to the given URL.
+ * @implicitCast
+ * @type {string}
+ * @see https://html.spec.whatwg.org/multipage/history.html#dom-location-href
+ */
+Location.prototype.href;
+
+/**
+ * Returns the Location object's URL's origin.
+ * @const {string}
+ * @see https://html.spec.whatwg.org/multipage/history.html#dom-location-origin
+ */
+Location.prototype.origin;
+
+/**
+ * Returns the Location object's URL's scheme. Can be set, to navigate to the
+ * same URL with a changed scheme.
+ * @type {string}
+ * @see https://html.spec.whatwg.org/multipage/history.html#dom-location-protocol
+ */
+Location.prototype.protocol;
+
+/**
+ * Returns the Location object's URL's host and port (if different from the
+ * default port for the scheme). Can be set, to navigate to the same URL with
+ * a changed host and port.
+ * @type {string}
+ * @see https://html.spec.whatwg.org/multipage/history.html#dom-location-host
+ */
+Location.prototype.host;
+
+/**
+ * Returns the Location object's URL's host. Can be set, to navigate to the
+ * same URL with a changed host.
+ * @type {string}
+ * @see https://html.spec.whatwg.org/multipage/history.html#dom-location-hostname
+ */
+Location.prototype.hostname;
+
+/**
+ * Returns the Location object's URL's port. Can be set, to navigate to the
+ * same URL with a changed port.
+ * @type {string}
+ * @see https://html.spec.whatwg.org/multipage/history.html#the-location-interface:dom-location-port
+ */
+Location.prototype.port;
+
+/**
+ * Returns the Location object's URL's path. Can be set, to navigate to the
+ * same URL with a changed path.
+ * @type {string}
+ * @see https://html.spec.whatwg.org/multipage/history.html#dom-location-pathname
+ */
+Location.prototype.pathname;
+
+/**
+ * Returns the Location object's URL's query (includes leading "?" if
+ * non-empty). Can be set, to navigate to the same URL with a changed query
+ * (ignores leading "?").
+ * @type {string}
+ * @see https://html.spec.whatwg.org/multipage/history.html#dom-location-search
+ */
+Location.prototype.search;
+
+/**
+ * Returns the Location object's URL's fragment (includes leading "#" if
+ * non-empty). Can be set, to navigate to the same URL with a changed fragment
+ * (ignores leading "#").
+ * @type {string}
+ * @see https://html.spec.whatwg.org/multipage/history.html#dom-location-hash
+ */
+Location.prototype.hash;
+
+/**
+ * Navigates to the given page.
+ * @param {string} url
+ * @return {undefined}
+ * @see https://html.spec.whatwg.org/multipage/history.html#dom-location-assign
+ */
+Location.prototype.assign = function(url) {};
+
+/**
+ * Removes the current page from the session history and navigates to the given
+ * page.
+ * @param {string} url
+ * @return {undefined}
+ * @see https://html.spec.whatwg.org/multipage/history.html#dom-location-replace
+ */
+Location.prototype.replace = function(url) {};
+
+/**
+ * Reloads the current page.
+ * @param {boolean=} forceReload If true, reloads the page from
+ *     the server. Defaults to false.
+ * @return {undefined}
+ * @see https://html.spec.whatwg.org/multipage/history.html#dom-location-reload
+ */
+Location.prototype.reload = function(forceReload) {};
+
+/**
+ * Returns a DOMStringList object listing the origins of the ancestor browsing
+ * contexts, from the parent browsing context to the top-level browsing
+ * context.
+ * @type {DOMStringList}
+ * @see https://html.spec.whatwg.org/multipage/history.html#dom-location-ancestororigins
+ */
+Location.prototype.ancestorOrigins;
+
 /**
  * @see http://www.whatwg.org/specs/web-apps/current-work/#popstateevent
  * @constructor
@@ -2812,26 +3825,15 @@ XMLHttpRequest.prototype.mozResponseArrayBuffer;
  */
 function XMLHttpRequestEventTarget() {}
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
+/** @override */
 XMLHttpRequestEventTarget.prototype.addEventListener = function(
-    type, listener, opt_useCapture) {};
+    type, listener, opt_options) {};
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
+/** @override */
 XMLHttpRequestEventTarget.prototype.removeEventListener = function(
-    type, listener, opt_useCapture) {};
+    type, listener, opt_options) {};
 
-/**
- * @override
- * @return {boolean}
- */
+/** @override */
 XMLHttpRequestEventTarget.prototype.dispatchEvent = function(evt) {};
 
 /**
@@ -2861,8 +3863,7 @@ function Image(opt_width, opt_height) {}
  * Dataset collection.
  * This is really a DOMStringMap but it behaves close enough to an object to
  * pass as an object.
- * @type {Object}
- * @const
+ * @const {!Object<string, string>}
  */
 HTMLElement.prototype.dataset;
 
@@ -2880,6 +3881,12 @@ function DOMTokenList() {}
  */
 DOMTokenList.prototype.length;
 
+/**
+ * Returns the string value applied to this Element.
+ * @type {string|undefined}
+ */
+DOMTokenList.prototype.value;
+
 /**
  * @param {number} index The index of the item to return.
  * @return {string} The CSS class at the specified index.
@@ -2906,6 +3913,22 @@ DOMTokenList.prototype.add = function(var_args) {};
  */
 DOMTokenList.prototype.remove = function(var_args) {};
 
+/**
+ * Replaces token with newToken.
+ * @param {string} token The CSS class to replace.
+ * @param {string} newToken The new CSS class to use.
+ * @return {undefined}
+ */
+DOMTokenList.prototype.replace = function(token, newToken) {};
+
+/**
+ * @param {string} token The token to query for.
+ * @return {boolean} Whether the token was found.
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/DOMTokenList/supports
+ * @nosideeffects
+ */
+DOMTokenList.prototype.supports = function(token) {};
+
 /**
  * @param {string} token The CSS class to toggle from this element.
  * @param {boolean=} opt_force True to add the class whether it exists
@@ -2924,11 +3947,18 @@ DOMTokenList.prototype.toggle = function(token, opt_force) {};
  */
 DOMTokenList.prototype.toString = function() {};
 
+/**
+ * @return {!IteratorIterable<string>} An iterator to go through all values of
+ *     the key/value pairs contained in this object.
+ * @nosideeffects
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/DOMTokenList/values
+ */
+DOMTokenList.prototype.values = function() {};
+
 /**
  * A better interface to CSS classes than className.
- * @type {!DOMTokenList}
+ * @const {!DOMTokenList}
  * @see https://developer.mozilla.org/en-US/docs/Web/API/Element/classList
- * @const
  */
 Element.prototype.classList;
 
@@ -2987,8 +4017,9 @@ ValidityState.prototype.valueMissing;
 HTMLButtonElement.prototype.autofocus;
 
 /**
- * @const
- * @type {NodeList<!HTMLLabelElement>}
+ * Can return null when hidden.
+ * See https://html.spec.whatwg.org/multipage/forms.html#dom-lfe-labels
+ * @const {?NodeList<!HTMLLabelElement>}
  */
 HTMLButtonElement.prototype.labels;
 
@@ -2996,8 +4027,7 @@ HTMLButtonElement.prototype.labels;
 HTMLButtonElement.prototype.validationMessage;
 
 /**
- * @const
- * @type {ValidityState}
+ * @const {ValidityState}
  */
 HTMLButtonElement.prototype.validity;
 
@@ -3018,6 +4048,7 @@ HTMLButtonElement.prototype.setCustomValidity = function(message) {};
 
 /**
  * @type {string}
+ * @implicitCast
  * @see http://www.w3.org/TR/html5/forms.html#attr-fs-formaction
  */
 HTMLButtonElement.prototype.formAction;
@@ -3048,6 +4079,7 @@ HTMLInputElement.prototype.formNoValidate;
 
 /**
  * @type {string}
+ * @implicitCast
  * @see http://www.w3.org/TR/html5/forms.html#attr-fs-formaction
  */
 HTMLInputElement.prototype.formAction;
@@ -3065,23 +4097,58 @@ HTMLInputElement.prototype.formEnctype;
 HTMLInputElement.prototype.formMethod;
 
 /**
- * @type {string}
- * @see http://www.w3.org/TR/html5/forms.html#attr-fs-formtarget
+ * @type {string}
+ * @see http://www.w3.org/TR/html5/forms.html#attr-fs-formtarget
+ */
+HTMLInputElement.prototype.formTarget;
+
+/**
+ * Can return null when hidden.
+ * See https://html.spec.whatwg.org/multipage/forms.html#dom-lfe-labels
+ * @const {?NodeList<!HTMLLabelElement>}
+ */
+HTMLInputElement.prototype.labels;
+
+/** @type {string} */
+HTMLInputElement.prototype.validationMessage;
+
+/**
+ * @type {number}
+ * @implicitCast
+ */
+HTMLInputElement.prototype.selectionStart;
+
+/**
+ * @type {number}
+ * @implicitCast
+ */
+HTMLInputElement.prototype.selectionEnd;
+
+/** @type {string} */
+HTMLInputElement.prototype.selectionDirection;
+
+/**
+ * @param {number} start
+ * @param {number} end
+ * @param {string=} direction
+ * @see https://html.spec.whatwg.org/#dom-textarea/input-setselectionrange
+ * @return {undefined}
  */
-HTMLInputElement.prototype.formTarget;
+HTMLInputElement.prototype.setSelectionRange = function(start, end, direction) {};
 
 /**
- * @const
- * @type {NodeList<!HTMLLabelElement>}
+ * @param {string} replacement
+ * @param {number=} start
+ * @param {number=} end
+ * @param {string=} selectionMode
+ * @see https://html.spec.whatwg.org/#dom-textarea/input-setrangetext
+ * @return {undefined}
  */
-HTMLInputElement.prototype.labels;
-
-/** @type {string} */
-HTMLInputElement.prototype.validationMessage;
+HTMLInputElement.prototype.setRangeText =
+    function(replacement, start, end, selectionMode) {};
 
 /**
- * @const
- * @type {ValidityState}
+ * @const {ValidityState}
  */
 HTMLInputElement.prototype.validity;
 
@@ -3107,8 +4174,9 @@ HTMLLabelElement.prototype.control;
 HTMLSelectElement.prototype.autofocus;
 
 /**
- * @const
- * @type {NodeList<!HTMLLabelElement>}
+ * Can return null when hidden.
+ * See https://html.spec.whatwg.org/multipage/forms.html#dom-lfe-labels
+ * @const {?NodeList<!HTMLLabelElement>}
  */
 HTMLSelectElement.prototype.labels;
 
@@ -3119,8 +4187,7 @@ HTMLSelectElement.prototype.selectedOptions;
 HTMLSelectElement.prototype.validationMessage;
 
 /**
- * @const
- * @type {ValidityState}
+ * @const {ValidityState}
  */
 HTMLSelectElement.prototype.validity;
 
@@ -3143,17 +4210,29 @@ HTMLSelectElement.prototype.setCustomValidity = function(message) {};
 HTMLTextAreaElement.prototype.autofocus;
 
 /**
- * @const
- * @type {NodeList<!HTMLLabelElement>}
+ * Can return null when hidden.
+ * See https://html.spec.whatwg.org/multipage/forms.html#dom-lfe-labels
+ * @const {?NodeList<!HTMLLabelElement>}
  */
 HTMLTextAreaElement.prototype.labels;
 
+/** @type {number} */
+HTMLTextAreaElement.prototype.maxLength;
+
+/** @type {number} */
+HTMLTextAreaElement.prototype.minLength;
+
+/** @type {string} */
+HTMLTextAreaElement.prototype.placeholder;
+
+/** @type {number} */
+HTMLTextAreaElement.prototype.textLength;
+
 /** @type {string} */
 HTMLTextAreaElement.prototype.validationMessage;
 
 /**
- * @const
- * @type {ValidityState}
+ * @const {ValidityState}
  */
 HTMLTextAreaElement.prototype.validity;
 
@@ -3193,6 +4272,7 @@ HTMLEmbedElement.prototype.height;
 
 /**
  * @type {string}
+ * @implicitCast
  * @see http://www.w3.org/TR/html5/the-embed-element.html#dom-embed-src
  */
 HTMLEmbedElement.prototype.src;
@@ -3206,10 +4286,20 @@ HTMLEmbedElement.prototype.type;
 // Fullscreen APIs.
 
 /**
- * @see http://www.w3.org/TR/2012/WD-fullscreen-20120703/#dom-element-requestfullscreen
- * @return {undefined}
+ * @record
+ * @see https://fullscreen.spec.whatwg.org/#dictdef-fullscreenoptions
+ */
+function FullscreenOptions() {}
+
+/** @type {string} */
+FullscreenOptions.prototype.navigationUI;
+
+/**
+ * @see https://fullscreen.spec.whatwg.org/#dom-element-requestfullscreen
+ * @param {!FullscreenOptions=} options
+ * @return {!Promise<undefined>}
  */
-Element.prototype.requestFullscreen = function() {};
+Element.prototype.requestFullscreen = function(options) {};
 
 /**
  * @type {boolean}
@@ -3288,7 +4378,7 @@ Document.prototype.webkitFullScreenKeyboardInputAllowed;
 Element.prototype.msRequestFullscreen = function() {};
 
 /** @return {void} */
-Element.prototype.msExitFullscreen = function() {};
+Document.prototype.msExitFullscreen = function() {};
 
 /** @type {boolean} */
 Document.prototype.msFullscreenEnabled;
@@ -3296,11 +4386,11 @@ Document.prototype.msFullscreenEnabled;
 /** @type {Element} */
 Document.prototype.msFullscreenElement;
 
-/** @type {number} */
-Element.ALLOW_KEYBOARD_INPUT = 1;
+/** @const {number} */
+Element.ALLOW_KEYBOARD_INPUT;
 
-/** @type {number} */
-Element.prototype.ALLOW_KEYBOARD_INPUT = 1;
+/** @const {number} */
+Element.prototype.ALLOW_KEYBOARD_INPUT;
 
 
 /**
@@ -3326,16 +4416,16 @@ MutationRecord.prototype.type;
 /** @type {Node} */
 MutationRecord.prototype.target;
 
-/** @type {NodeList<!Node>} */
+/** @type {!NodeList<!Node>} */
 MutationRecord.prototype.addedNodes;
 
-/** @type {NodeList<!Node>} */
+/** @type {!NodeList<!Node>} */
 MutationRecord.prototype.removedNodes;
 
-/** @type {Node} */
+/** @type {?Node} */
 MutationRecord.prototype.previousSibling;
 
-/** @type {Node} */
+/** @type {?Node} */
 MutationRecord.prototype.nextSibling;
 
 /** @type {?string} */
@@ -3350,7 +4440,7 @@ MutationRecord.prototype.oldValue;
 
 /**
  * @see http://www.w3.org/TR/domcore/#mutation-observers
- * @param {function(Array<MutationRecord>, MutationObserver)} callback
+ * @param {function(!Array<!MutationRecord>, !MutationObserver)} callback
  * @constructor
  */
 function MutationObserver(callback) {}
@@ -3426,19 +4516,20 @@ Document.prototype.msHidden;
  * @see http://www.w3.org/TR/components-intro/
  * @see http://w3c.github.io/webcomponents/spec/custom/#extensions-to-document-interface-to-register
  * @param {string} type
- * @param {{extends: (string|undefined), prototype: (Object|undefined)}=} options
- * @return {!Function} a constructor for the new tag. A generic function is the best we
- *     can do here as it allows the return value to be annotated properly
- *     at the call site.
+ * @param {{extends: (string|undefined), prototype: (Object|undefined)}=}
+ *     options
+ * @return {function(new:Element, ...*)} a constructor for the new tag.
+ * @deprecated document.registerElement() is deprecated in favor of
+ *     customElements.define()
  */
 Document.prototype.registerElement = function(type, options) {};
 
 /**
- * This method is deprecated and should be removed by the end of 2014.
  * @see http://www.w3.org/TR/components-intro/
  * @see http://w3c.github.io/webcomponents/spec/custom/#extensions-to-document-interface-to-register
  * @param {string} type
  * @param {{extends: (string|undefined), prototype: (Object|undefined)}} options
+ * @deprecated This method has been removed and will be removed soon from this file.
  */
 Document.prototype.register = function(type, options) {};
 
@@ -3450,6 +4541,7 @@ Document.prototype.fonts;
 
 
 /**
+ * @type {?HTMLScriptElement}
  * @see https://developer.mozilla.org/en-US/docs/Web/API/Document/currentScript
  */
 Document.prototype.currentScript;
@@ -3481,31 +4573,6 @@ ShadowRoot.prototype.host;
 ShadowRoot.prototype.getElementById = function(id) {};
 
 
-/**
- * @param {string} className
- * @return {!NodeList<!Element>}
- * @nosideeffects
- */
-ShadowRoot.prototype.getElementsByClassName = function(className) {};
-
-
-/**
- * @param {string} tagName
- * @return {!NodeList<!Element>}
- * @nosideeffects
- */
-ShadowRoot.prototype.getElementsByTagName = function(tagName) {};
-
-
-/**
- * @param {string} namespace
- * @param {string} localName
- * @return {!NodeList<!Element>}
- * @nosideeffects
- */
-ShadowRoot.prototype.getElementsByTagNameNS = function(namespace, localName) {};
-
-
 /**
  * @return {Selection}
  * @nosideeffects
@@ -3523,31 +4590,36 @@ ShadowRoot.prototype.elementFromPoint = function(x, y) {};
 
 
 /**
- * @type {boolean}
+ * @param {number} x
+ * @param {number} y
+ * @return {!IArrayLike<!Element>}
+ * @nosideeffects
  */
-ShadowRoot.prototype.applyAuthorStyles;
+ShadowRoot.prototype.elementsFromPoint = function(x, y) {};
 
 
 /**
- * @type {boolean}
+ * @type {?Element}
  */
-ShadowRoot.prototype.resetStyleInheritance;
+ShadowRoot.prototype.activeElement;
 
 
 /**
- * @type {Element}
+ * @type {string}
  */
-ShadowRoot.prototype.activeElement;
+ShadowRoot.prototype.mode;
 
 
 /**
  * @type {?ShadowRoot}
+ * @deprecated
  */
 ShadowRoot.prototype.olderShadowRoot;
 
 
 /**
  * @type {string}
+ * @implicitCast
  */
 ShadowRoot.prototype.innerHTML;
 
@@ -3567,7 +4639,7 @@ ShadowRoot.prototype.styleSheets;
 function HTMLContentElement() {}
 
 /**
- * @type {!string}
+ * @type {string}
  */
 HTMLContentElement.prototype.select;
 
@@ -3669,7 +4741,7 @@ HTMLSourceElement.prototype.media;
 /** @type {string} */
 HTMLSourceElement.prototype.sizes;
 
-/** @type {string} */
+/** @type {string} @implicitCast */
 HTMLSourceElement.prototype.src;
 
 /** @type {string} */
@@ -3851,6 +4923,19 @@ HTMLTemplateElement.prototype.content;
  */
 HTMLLinkElement.prototype.import;
 
+/**
+ * @type {string}
+ * @see https://html.spec.whatwg.org/#attr-link-as
+ * @see https://w3c.github.io/preload/#as-attribute
+ */
+HTMLLinkElement.prototype.as;
+
+/**
+ * @see https://html.spec.whatwg.org/#attr-link-crossorigin
+ * @type {string}
+ */
+HTMLLinkElement.prototype.crossOrigin;
+
 
 /**
  * @return {boolean}
@@ -3909,6 +4994,11 @@ HTMLFieldSetElement.prototype.willValidate;
  */
 function RadioNodeList() {}
 
+/**
+ * @type {string}
+ * @see https://html.spec.whatwg.org/multipage/infrastructure.html#radionodelist
+ */
+RadioNodeList.prototype.value;
 
 
 /**
@@ -3923,6 +5013,37 @@ function HTMLDataListElement() {}
 HTMLDataListElement.prototype.options;
 
 
+/**
+ * @return {boolean}
+ * @see https://html.spec.whatwg.org/multipage/iframe-embed-object.html#the-object-element
+ */
+HTMLObjectElement.prototype.checkValidity;
+
+/**
+ * @param {string} message
+ * @see https://html.spec.whatwg.org/multipage/iframe-embed-object.html#the-object-element
+ * @return {undefined}
+ */
+HTMLObjectElement.prototype.setCustomValidity;
+
+/**
+ * @type {string}
+ * @see https://html.spec.whatwg.org/multipage/iframe-embed-object.html#the-object-element
+ */
+HTMLObjectElement.prototype.validationMessage;
+
+/**
+ * @type {!ValidityState}
+ * @see https://html.spec.whatwg.org/multipage/iframe-embed-object.html#the-object-element
+ */
+HTMLObjectElement.prototype.validity;
+
+/**
+ * @type {boolean}
+ * @see https://html.spec.whatwg.org/multipage/iframe-embed-object.html#the-object-element
+ */
+HTMLObjectElement.prototype.willValidate;
+
 
 /**
  * @see https://html.spec.whatwg.org/multipage/forms.html#the-output-element
@@ -3962,7 +5083,7 @@ HTMLOutputElement.prototype.defaultValue;
 HTMLOutputElement.prototype.value;
 
 /**
- * @const {NodeList<!HTMLLabelElement>}
+ * @const {?NodeList<!HTMLLabelElement>}
  */
 HTMLOutputElement.prototype.labels;
 
@@ -4008,7 +5129,7 @@ HTMLProgressElement.prototype.max;
 HTMLProgressElement.prototype.position;
 
 
-/** @type {NodeList<!Node>} */
+/** @type {?NodeList<!Node>} */
 HTMLProgressElement.prototype.labels;
 
 
@@ -4025,7 +5146,7 @@ function HTMLTrackElement() {}
 HTMLTrackElement.prototype.kind;
 
 
-/** @type {string} */
+/** @type {string} @implicitCast */
 HTMLTrackElement.prototype.src;
 
 
@@ -4045,7 +5166,7 @@ HTMLTrackElement.prototype.default;
 HTMLTrackElement.prototype.readyState;
 
 
-/** @const {TextTrack} */
+/** @const {!TextTrack} */
 HTMLTrackElement.prototype.track;
 
 
@@ -4082,15 +5203,28 @@ HTMLMeterElement.prototype.high;
 HTMLMeterElement.prototype.optimum;
 
 
-/** @type {NodeList<!Node>} */
+/** @type {?NodeList<!Node>} */
 HTMLMeterElement.prototype.labels;
 
 
+/**
+ * @interface
+ * @see https://storage.spec.whatwg.org/#api
+ */
+function NavigatorStorage() {};
+
+/**
+ * @type {!StorageManager}
+ */
+NavigatorStorage.prototype.storage;
+
 /**
  * @constructor
+ * @implements NavigatorStorage
  * @see https://www.w3.org/TR/html5/webappapis.html#navigator
  */
 function Navigator() {}
+
 /**
  * @type {string}
  * @see https://www.w3.org/TR/html5/webappapis.html#dom-navigator-appcodename
@@ -4182,13 +5316,13 @@ Navigator.prototype.unregisterProtocolHandler = function(scheme, url) {}
 Navigator.prototype.unregisterContentHandler = function(mimeType, url) {}
 
 /**
- * @type {MimeTypeArray}
+ * @type {!MimeTypeArray}
  * @see https://www.w3.org/TR/html5/webappapis.html#dom-navigator-mimetypes
  */
 Navigator.prototype.mimeTypes;
 
 /**
- * @type {PluginArray}
+ * @type {!PluginArray}
  * @see https://www.w3.org/TR/html5/webappapis.html#dom-navigator-plugins
  */
 Navigator.prototype.plugins;
@@ -4200,6 +5334,79 @@ Navigator.prototype.plugins;
  */
 Navigator.prototype.javaEnabled = function() {};
 
+/**
+ * @type {number}
+ * @see https://developers.google.com/web/updates/2017/12/device-memory
+ * https://github.com/w3c/device-memory
+ */
+Navigator.prototype.deviceMemory;
+
+/**
+ * @type {!StorageManager}
+ * @see https://storage.spec.whatwg.org
+ */
+Navigator.prototype.storage;
+
+/**
+ * @param {!ShareData=} data
+ * @return {boolean}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/Navigator/canShare
+ */
+Navigator.prototype.canShare = function(data) {};
+
+/**
+ * @param {!ShareData=} data
+ * @return {!Promise<undefined>}
+ * @see https://wicg.github.io/web-share/#share-method
+ */
+Navigator.prototype.share = function(data) {};
+
+/**
+ * @type {number}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/NavigatorConcurrentHardware/hardwareConcurrency
+ */
+Navigator.prototype.hardwareConcurrency;
+
+/**
+ * @constructor
+ * @implements NavigatorStorage
+ * @see https://html.spec.whatwg.org/multipage/workers.html#the-workernavigator-object
+ */
+function WorkerNavigator() {}
+
+/**
+ * @type {number}
+ * @see https://developers.google.com/web/updates/2017/12/device-memory
+ * https://github.com/w3c/device-memory
+ */
+WorkerNavigator.prototype.deviceMemory;
+
+/**
+ * @type {number}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/NavigatorConcurrentHardware/hardwareConcurrency
+ */
+WorkerNavigator.prototype.hardwareConcurrency;
+
+/**
+ * @type {!StorageManager}
+ * @see https://storage.spec.whatwg.org
+ */
+WorkerNavigator.prototype.storage;
+
+/**
+ * @record
+ * @see https://wicg.github.io/web-share/#sharedata-dictionary
+ */
+function ShareData() {}
+
+/** @type {string|undefined} */
+ShareData.prototype.title;
+
+/** @type {string|undefined} */
+ShareData.prototype.text;
+
+/** @type {string|undefined} */
+ShareData.prototype.url;
 
 /**
  * @constructor
@@ -4291,3 +5498,187 @@ Plugin.prototype.length;
 
 /** @type {string} */
 Plugin.prototype.name;
+
+/**
+ * @see https://html.spec.whatwg.org/multipage/custom-elements.html#customelementregistry
+ * @constructor
+ */
+function CustomElementRegistry() {}
+
+/**
+ * @param {string} tagName
+ * @param {function(new:HTMLElement)} klass
+ * @param {{extends: string}=} options
+ * @return {undefined}
+ */
+CustomElementRegistry.prototype.define = function (tagName, klass, options) {};
+
+/**
+ * @param {string} tagName
+ * @return {function(new:HTMLElement)|undefined}
+ */
+CustomElementRegistry.prototype.get = function(tagName) {};
+
+/**
+ * @param {string} tagName
+ * @return {!Promise<undefined>}
+ */
+CustomElementRegistry.prototype.whenDefined = function(tagName) {};
+
+/**
+ * @param {!Node} root
+ * @return {undefined}
+ */
+CustomElementRegistry.prototype.upgrade = function(root) {};
+
+/** @type {!CustomElementRegistry} */
+var customElements;
+
+/**
+ * @constructor
+ * @extends {HTMLElement}
+ */
+function HTMLSlotElement() {}
+
+/** @typedef {{flatten: boolean}} */
+var AssignedNodesOptions;
+
+/**
+ * @param {!AssignedNodesOptions=} options
+ * @return {!Array<!Node>}
+ */
+HTMLSlotElement.prototype.assignedNodes = function(options) {};
+
+/**
+ * @param {!AssignedNodesOptions=} options
+ * @return {!Array<!HTMLElement>}
+ */
+HTMLSlotElement.prototype.assignedElements = function(options) {};
+
+/** @type {boolean} */
+Event.prototype.composed;
+
+/**
+ * @return {!Array<!EventTarget>}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/Event/composedPath
+ */
+Event.prototype.composedPath = function() {};
+
+/**
+ * @constructor
+ * @param {{
+ *     firesTouchEvents: (string|undefined),
+ *     pointerMovementScrolls: (string|undefined)
+ *   }=} opt_options
+ */
+function InputDeviceCapabilities(opt_options){}
+
+/** @type {boolean} */
+InputDeviceCapabilities.prototype.firesTouchEvents;
+
+/** @type {boolean} */
+InputDeviceCapabilities.prototype.pointerMovementScrolls;
+
+/** @type {?InputDeviceCapabilities} */
+MouseEvent.prototype.sourceCapabilities;
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/VisualViewport
+ * @constructor
+ * @implements {EventTarget}
+ */
+function VisualViewport() {}
+
+/** @type {number} */
+VisualViewport.prototype.offsetLeft;
+
+/** @type {number} */
+VisualViewport.prototype.offsetTop;
+
+/** @type {number} */
+VisualViewport.prototype.pageLeft;
+
+/** @type {number} */
+VisualViewport.prototype.pageTop;
+
+/** @type {number} */
+VisualViewport.prototype.width;
+
+/** @type {number} */
+VisualViewport.prototype.height;
+
+/** @type {number} */
+VisualViewport.prototype.scale;
+
+/** @override */
+VisualViewport.prototype.addEventListener = function(type, listener,
+    opt_options) {};
+
+/** @override */
+VisualViewport.prototype.removeEventListener = function(type, listener,
+    opt_options) {};
+
+/** @override */
+VisualViewport.prototype.dispatchEvent = function(evt) {};
+
+/** @type {?function(!Event)} */
+VisualViewport.prototype.onresize;
+
+/** @type {?function(!Event)} */
+VisualViewport.prototype.onscroll;
+
+/**
+ * @see https://storage.spec.whatwg.org/
+ * @constructor
+ */
+function StorageManager() {}
+
+/** @return {!Promise<boolean>} */
+StorageManager.prototype.persisted = function() {};
+
+/** @return {!Promise<boolean>} */
+StorageManager.prototype.persist = function() {};
+
+/** @return {!Promise<StorageEstimate>} */
+StorageManager.prototype.estimate = function() {};
+
+/**
+ * @see https://storage.spec.whatwg.org/
+ * @typedef {{
+ *   usage: number,
+ *   quota: number
+ * }}
+ */
+var StorageEstimate;
+
+/*
+ * Focus Management APIs
+ *
+ * See https://html.spec.whatwg.org/multipage/interaction.html#focus-management-apis
+ */
+
+
+/**
+ * @type {?Element}
+ * @see https://html.spec.whatwg.org/multipage/interaction.html#dom-document-activeelement
+ */
+Document.prototype.activeElement;
+
+/**
+ * @see https://html.spec.whatwg.org/multipage/interaction.html#dom-document-hasfocus
+ * @return {boolean}
+ */
+Document.prototype.hasFocus = function() {};
+
+/**
+ * @param {{preventScroll: boolean}=} options
+ * @return {undefined}
+ * @see https://html.spec.whatwg.org/multipage/interaction.html#dom-focus
+ */
+Element.prototype.focus = function(options) {};
+
+/**
+ * @return {undefined}
+ * @see https://html.spec.whatwg.org/multipage/interaction.html#dom-blur
+ */
+Element.prototype.blur = function() {};
diff --git a/javascript/externs/web/ie_css.js b/javascript/externs/web/ie_css.js
index 359b9ceb4194..0eb7d3ba83ea 100644
--- a/javascript/externs/web/ie_css.js
+++ b/javascript/externs/web/ie_css.js
@@ -252,6 +252,9 @@ CSSProperties.prototype.MsWritingMode;
 /** @type {string} */
 CSSProperties.prototype.MsZoom;
 
+/** @type {string} */
+CSSProperties.prototype.msUserSelect;
+
 // See: http://msdn.microsoft.com/en-us/library/windows/apps/Hh702466.aspx
 
 /** @type {string} */
diff --git a/javascript/externs/web/ie_dom.js b/javascript/externs/web/ie_dom.js
index 7ed5e9fdac5d..b9cfd3bd0abb 100644
--- a/javascript/externs/web/ie_dom.js
+++ b/javascript/externs/web/ie_dom.js
@@ -120,14 +120,6 @@ XMLDOMDocument.prototype.abort = function() {};
  */
 XMLDOMDocument.prototype.createNode = function(type, name, namespaceURI) {};
 
-/**
- * @param {string} xmlSource
- * @return {undefined}
- * @see http://msdn.microsoft.com/en-us/library/ms762722(VS.85).aspx
- * @override
- */
-XMLDOMDocument.prototype.load = function(xmlSource) {};
-
 /**
  * @param {string} xmlString
  * @return {boolean}
@@ -179,13 +171,12 @@ Node.prototype.document;
  * Inserts the given HTML text into the element at the location.
  * @param {string} sWhere Where to insert the HTML text, one of 'beforeBegin',
  *     'afterBegin', 'beforeEnd', 'afterEnd'.
- * @param {string} sText HTML text to insert.
+ * @param {!TrustedHTML|string} sText HTML text to insert.
  * @see http://msdn.microsoft.com/en-us/library/ms536452(VS.85).aspx
  * @return {undefined}
  */
 Node.prototype.insertAdjacentHTML = function(sWhere, sText) {};
 
-
 /**
  * @type {*}
  * @see http://msdn.microsoft.com/en-us/library/ms762308(VS.85).aspx
@@ -204,12 +195,6 @@ Node.prototype.nodeTypeString;
  */
 Node.prototype.parsed;
 
-/**
- * @type {Element}
- * @see http://msdn.microsoft.com/en-us/library/ms534327(VS.85).aspx
- */
-Node.prototype.parentElement;
-
 /**
  * @type {boolean}
  * @see http://msdn.microsoft.com/en-us/library/ms753816(VS.85).aspx
@@ -304,7 +289,7 @@ ClipboardData.prototype.getData = function(type) { };
  * @type {!Window}
  * @see https://developer.mozilla.org/en/DOM/window
  */
-var window;
+ var window;
 
 /**
  * @see http://msdn.microsoft.com/en-us/library/ms535220(VS.85).aspx
@@ -354,11 +339,13 @@ Window.prototype.offscreenBuffering;
 
 /**
  * @see http://msdn.microsoft.com/en-us/library/ms534389(VS.85).aspx
+ * @type {number|undefined}
  */
 Window.prototype.screenLeft;
 
 /**
  * @see http://msdn.microsoft.com/en-us/library/ms534389(VS.85).aspx
+ * @type {number|undefined}
  */
 Window.prototype.screenTop;
 
@@ -388,26 +375,6 @@ Window.prototype.detachEvent;
  */
 Window.prototype.execScript;
 
-/**
- * @see http://msdn.microsoft.com/en-us/library/ms536425(VS.85).aspx
- */
-Window.prototype.focus;
-
-/**
- * @param {number} x
- * @param {number} y
- * @see http://msdn.microsoft.com/en-us/library/ms536618(VS.85).aspx
- * @return {undefined}
- */
-Window.prototype.moveBy = function(x, y) {};
-
-/**
- * @param {number} x
- * @param {number} y
- * @see http://msdn.microsoft.com/en-us/library/ms536626(VS.85).aspx
- * @return {undefined}
- */
-Window.prototype.moveTo = function(x, y) {};
 
 /**
  * @see http://msdn.microsoft.com/en-us/library/ms536638(VS.85).aspx
@@ -422,29 +389,29 @@ Window.prototype.navigate;
  * @return {Window}
  * @see http://msdn.microsoft.com/en-us/library/ms536651(VS.85).aspx
  */
-Window.prototype.open = function(opt_url, opt_windowName, opt_windowFeatures,
-                                 opt_replace) {};
+ Window.prototype.open = function(opt_url, opt_windowName, opt_windowFeatures,
+    opt_replace) {};
 
 /**
- * @see http://msdn.microsoft.com/en-us/library/ms536672(VS.85).aspx
- * @return {undefined}
- */
+* @see http://msdn.microsoft.com/en-us/library/ms536672(VS.85).aspx
+* @return {undefined}
+*/
 Window.prototype.print = function() {};
 
 /**
- * @param {number} width
- * @param {number} height
- * @see http://msdn.microsoft.com/en-us/library/ms536722(VS.85).aspx
- * @return {undefined}
- */
+* @param {number} width
+* @param {number} height
+* @see http://msdn.microsoft.com/en-us/library/ms536722(VS.85).aspx
+* @return {undefined}
+*/
 Window.prototype.resizeBy = function(width, height) {};
 
 /**
- * @param {number} width
- * @param {number} height
- * @see http://msdn.microsoft.com/en-us/library/ms536723(VS.85).aspx
- * @return {undefined}
- */
+* @param {number} width
+* @param {number} height
+* @see http://msdn.microsoft.com/en-us/library/ms536723(VS.85).aspx
+* @return {undefined}
+*/
 Window.prototype.resizeTo = function(width, height) {};
 
 /**
@@ -469,32 +436,10 @@ Window.prototype.showModelessDialog;
 Window.prototype.external;
 
 /**
- * @see http://msdn.microsoft.com/en-us/library/ms535864(VS.85).aspx
- * @param {number|string} delta The number of entries to go back, or
- *     the URL to which to go back. (URL form is supported only in IE)
- * @return {undefined}
- */
-History.prototype.go = function(delta) {};
-
-/**
- * @see http://msdn.microsoft.com/en-us/library/ms535864(VS.85).aspx
- * @param {number=} opt_distance The number of entries to go back
- *     (Mozilla doesn't support distance -- use #go instead)
- * @return {undefined}
- */
-History.prototype.back = function(opt_distance) {};
-
-/**
- * @see http://msdn.microsoft.com/en-us/library/ms535864(VS.85).aspx
- * @type {number}
- */
-History.prototype.length;
-
-/**
- * @see http://msdn.microsoft.com/en-us/library/ms535864(VS.85).aspx
- * @return {undefined}
+ * @see https://msdn.microsoft.com/en-us/ie/dn265046(v=vs.94)
+ * @const {!Object}
  */
-History.prototype.forward = function() {};
+Window.prototype.msCrypto;
 
 /**
  * @type {boolean}
@@ -516,12 +461,6 @@ HTMLFrameElement.prototype.contentWindow;
  */
 HTMLIFrameElement.prototype.allowTransparency;
 
-/**
- * @type {Window}
- * @see http://msdn.microsoft.com/en-us/library/ms533692(VS.85).aspx
- */
-HTMLIFrameElement.prototype.contentWindow;
-
 /**
  * @see http://msdn.microsoft.com/en-us/library/ms536385(VS.85).aspx
  */
@@ -761,24 +700,6 @@ TextRange.prototype.select = function() {};
  */
 TextRange.prototype.setEndPoint;
 
-/**
- * @return {undefined}
- * @see http://msdn.microsoft.com/en-us/library/ms536418(VS.85).aspx
- */
-Selection.prototype.clear = function() {};
-
-/**
- * @return {TextRange|ControlRange}
- * @see http://msdn.microsoft.com/en-us/library/ms536394(VS.85).aspx
- */
-Selection.prototype.createRange = function() {};
-
-/**
- * @return {Array<TextRange>}
- * @see http://msdn.microsoft.com/en-us/library/ms536396(VS.85).aspx
- */
-Selection.prototype.createRangeCollection = function() {};
-
 /**
  * @constructor
  * @see http://msdn.microsoft.com/en-us/library/ms537447(VS.85).aspx
@@ -791,11 +712,6 @@ Document.prototype.loadXML;
 
 // http://msdn.microsoft.com/en-us/library/ms531073(VS.85).aspx
 
-/**
- * @see http://msdn.microsoft.com/en-us/library/ms533065(VS.85).aspx
- */
-Document.prototype.activeElement;
-
 /**
  * @see http://msdn.microsoft.com/en-us/library/ms533553(VS.85).aspx
  */
@@ -806,11 +722,6 @@ Document.prototype.charset;
  */
 Document.prototype.cookie;
 
-/**
- * @see http://msdn.microsoft.com/en-us/library/ms533714(VS.85).aspx
- */
-Document.prototype.defaultCharset;
-
 /**
  * @see http://msdn.microsoft.com/en-us/library/ms533731(VS.85).aspx
  */
@@ -843,6 +754,7 @@ Document.prototype.fileSize;
 
 /**
  * @see http://msdn.microsoft.com/en-us/library/ms534331(VS.85).aspx
+ * @type {?Window}
  */
 Document.prototype.parentWindow;
 
@@ -857,12 +769,6 @@ Document.prototype.protocol;
  */
 HTMLDocument.prototype.readyState;
 
-/**
- * @type {Selection}
- * @see http://msdn.microsoft.com/en-us/library/ms535869(VS.85).aspx
- */
-Document.prototype.selection;
-
 /**
  * @see http://msdn.microsoft.com/en-us/library/ms534704(VS.85).aspx
  */
@@ -914,12 +820,6 @@ Document.prototype.detachEvent;
  */
 Document.prototype.focus;
 
-/**
- * @see http://msdn.microsoft.com/en-us/library/ms536447(VS.85).aspx
- * @return {boolean}
- */
-Document.prototype.hasFocus = function() {};
-
 /**
  * @see http://msdn.microsoft.com/en-us/library/ms536614(VS.85).aspx
  */
@@ -965,6 +865,7 @@ Document.prototype.namespaces;
 
 /**
  * @see http://msdn.microsoft.com/en-us/library/ms537487(VS.85).aspx
+ * @type {!HTMLCollection<!HTMLScriptElement>}
  */
 Document.prototype.scripts;
 
@@ -1008,7 +909,8 @@ Element.prototype.componentFromPoint = function(iCoordX, iCoordY) {};
 
 
 /**
- * @type {boolean}
+ * TODO(tjgq): Make this string once existing usages have been migrated.
+ * @type {string|boolean}
  * @see http://msdn.microsoft.com/en-us/library/ms533690(VS.85).aspx
  */
 Element.prototype.contentEditable;
@@ -1051,11 +953,18 @@ Element.prototype.fireEvent;
 Element.prototype.hideFocus;
 
 /**
+ * @type {string}
+ * @implicitCast
+ *
+ * TODO(lharker): remove the @implicitCast to enforce assigning an explicit
+ * string to innerText instead of relying on coercion.
+ *
  * @see http://msdn.microsoft.com/en-us/library/ms533899.aspx
  */
 Element.prototype.innerText;
 
 /**
+ * @type {boolean}
  * @see http://msdn.microsoft.com/en-us/library/ms537838(VS.85).aspx
  */
 Element.prototype.isContentEditable;
@@ -1098,18 +1007,6 @@ Element.prototype.onmouseenter;
  */
 Element.prototype.onmouseleave;
 
-/**
- * @type {?function(Event)}
- * @see http://msdn.microsoft.com/en-us/library/ms536969(VS.85).aspx
- */
-Element.prototype.onselectstart;
-
-/**
- * @type {string}
- * @see http://msdn.microsoft.com/en-us/library/aa752326(VS.85).aspx
- */
-Element.prototype.outerHTML;
-
 /**
  * @see http://msdn.microsoft.com/en-us/library/ms536689(VS.85).aspx
  * @return {undefined}
@@ -1215,90 +1112,90 @@ AlphaImageLoaderFilter.prototype.sizingMethod;
  * @constructor
  * @see http://msdn.microsoft.com/en-us/library/ms535866(VS.85).aspx
  */
-function Location() {}
-
-/**
- * @see http://trac.webkit.org/changeset/113945
- * @type {DOMStringList}
- */
-Location.prototype.ancestorOrigins;
-
-/**
- * @see http://msdn.microsoft.com/en-us/library/ms533775(VS.85).aspx
- * @type {string}
- */
-Location.prototype.hash;
-
-/**
- * @see http://msdn.microsoft.com/en-us/library/ms533784(VS.85).aspx
- * @type {string}
- */
-Location.prototype.host;
-
-/**
- * @see http://msdn.microsoft.com/en-us/library/ms533785(VS.85).aspx
- * @type {string}
- */
-Location.prototype.hostname;
-
-/**
- * @see http://msdn.microsoft.com/en-us/library/ms533867(VS.85).aspx
- * @type {string}
- */
-Location.prototype.href;
-
-/**
- * @see https://docs.google.com/document/view?id=1r_VTFKApVOaNIkocrg0z-t7lZgzisTuGTXkdzAk4gLU&hl=en
- * @type {string}
- */
-Location.prototype.origin;
-
-/**
- * @see http://msdn.microsoft.com/en-us/library/ms534332(VS.85).aspx
- * @type {string}
- */
-Location.prototype.pathname;
-
-/**
- * @see http://msdn.microsoft.com/en-us/library/ms534342(VS.85).aspx
- */
-Location.prototype.port;
-
-/**
- * @see http://msdn.microsoft.com/en-us/library/ms534353(VS.85).aspx
- * @type {string}
- */
-Location.prototype.protocol;
-
-/**
- * @see http://msdn.microsoft.com/en-us/library/ms534620(VS.85).aspx
- * @type {string}
- */
-Location.prototype.search;
-
-/**
- * @see http://msdn.microsoft.com/en-us/library/ms536342(VS.85).aspx
- * @param {string} url
- * @return {undefined}
- */
-Location.prototype.assign = function(url) {};
-
-/**
- * @param {boolean=} opt_forceReload If true, reloads the page from
- *     the server. Defaults to false.
- * @see http://msdn.microsoft.com/en-us/library/ms536691(VS.85).aspx
- * @return {undefined}
- */
-Location.prototype.reload = function(opt_forceReload) {};
-
-/**
- * @param {string} url
- * @see http://msdn.microsoft.com/en-us/library/ms536712(VS.85).aspx
- * @return {undefined}
- */
-Location.prototype.replace = function(url) {};
-
-
+ function Location() {}
+
+ /**
+  * @see http://trac.webkit.org/changeset/113945
+  * @type {DOMStringList}
+  */
+ Location.prototype.ancestorOrigins;
+ 
+ /**
+  * @see http://msdn.microsoft.com/en-us/library/ms533775(VS.85).aspx
+  * @type {string}
+  */
+ Location.prototype.hash;
+ 
+ /**
+  * @see http://msdn.microsoft.com/en-us/library/ms533784(VS.85).aspx
+  * @type {string}
+  */
+ Location.prototype.host;
+ 
+ /**
+  * @see http://msdn.microsoft.com/en-us/library/ms533785(VS.85).aspx
+  * @type {string}
+  */
+ Location.prototype.hostname;
+ 
+ /**
+  * @see http://msdn.microsoft.com/en-us/library/ms533867(VS.85).aspx
+  * @type {string}
+  */
+ Location.prototype.href;
+ 
+ /**
+  * @see https://docs.google.com/document/view?id=1r_VTFKApVOaNIkocrg0z-t7lZgzisTuGTXkdzAk4gLU&hl=en
+  * @type {string}
+  */
+ Location.prototype.origin;
+ 
+ /**
+  * @see http://msdn.microsoft.com/en-us/library/ms534332(VS.85).aspx
+  * @type {string}
+  */
+ Location.prototype.pathname;
+ 
+ /**
+  * @see http://msdn.microsoft.com/en-us/library/ms534342(VS.85).aspx
+  */
+ Location.prototype.port;
+ 
+ /**
+  * @see http://msdn.microsoft.com/en-us/library/ms534353(VS.85).aspx
+  * @type {string}
+  */
+ Location.prototype.protocol;
+ 
+ /**
+  * @see http://msdn.microsoft.com/en-us/library/ms534620(VS.85).aspx
+  * @type {string}
+  */
+ Location.prototype.search;
+ 
+ /**
+  * @see http://msdn.microsoft.com/en-us/library/ms536342(VS.85).aspx
+  * @param {string} url
+  * @return {undefined}
+  */
+ Location.prototype.assign = function(url) {};
+ 
+ /**
+  * @param {boolean=} opt_forceReload If true, reloads the page from
+  *     the server. Defaults to false.
+  * @see http://msdn.microsoft.com/en-us/library/ms536691(VS.85).aspx
+  * @return {undefined}
+  */
+ Location.prototype.reload = function(opt_forceReload) {};
+ 
+ /**
+  * @param {string} url
+  * @see http://msdn.microsoft.com/en-us/library/ms536712(VS.85).aspx
+  * @return {undefined}
+  */
+ Location.prototype.replace = function(url) {};
+ 
+ 
 // For IE, returns an object representing key-value pairs for all the global
 // variables prefixed with str, e.g. test*
 
diff --git a/javascript/externs/web/ie_event.js b/javascript/externs/web/ie_event.js
index 30763e5a55c2..30e1694188d5 100644
--- a/javascript/externs/web/ie_event.js
+++ b/javascript/externs/web/ie_event.js
@@ -71,7 +71,7 @@ Event.prototype.propertyName;
 /** @type {string} */
 Event.prototype.qualifier;
 
-/** @type {number} */
+/** @type {?} */
 Event.prototype.reason;
 
 /** @type {Object<*>} */
@@ -135,13 +135,13 @@ MSPointerPoint.prototype.pointerType;
  */
 function MSPointerEvent() {}
 
-/** @type {number} */
+/** @const {number} */
 MSPointerEvent.MSPOINTER_TYPE_MOUSE;
 
-/** @type {number} */
+/** @const {number} */
 MSPointerEvent.MSPOINTER_TYPE_PEN;
 
-/** @type {number} */
+/** @const {number} */
 MSPointerEvent.MSPOINTER_TYPE_TOUCH;
 
 /** @type {number} */
diff --git a/javascript/externs/web/mediasource.js b/javascript/externs/web/mediasource.js
index d921537a7a72..283d24d7f7ab 100644
--- a/javascript/externs/web/mediasource.js
+++ b/javascript/externs/web/mediasource.js
@@ -27,26 +27,15 @@
  */
 function MediaSource() {}
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-MediaSource.prototype.addEventListener = function(
-    type, listener, opt_useCapture) {};
+/** @override */
+MediaSource.prototype.addEventListener = function(type, listener, opt_options) {
+};
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
+/** @override */
 MediaSource.prototype.removeEventListener = function(
-    type, listener, opt_useCapture) {};
+    type, listener, opt_options) {};
 
-/**
- * @override
- * @return {boolean}
- */
+/** @override */
 MediaSource.prototype.dispatchEvent = function(evt) {};
 
 /** @type {Array<SourceBuffer>} */
@@ -105,26 +94,15 @@ MediaSource.isTypeSupported = function(type) {};
  */
 function SourceBuffer() {}
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
+/** @override */
 SourceBuffer.prototype.addEventListener = function(
-    type, listener, opt_useCapture) {};
+    type, listener, opt_options) {};
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
+/** @override */
 SourceBuffer.prototype.removeEventListener = function(
-    type, listener, opt_useCapture) {};
+    type, listener, opt_options) {};
 
-/**
- * @override
- * @return {boolean}
- */
+/** @override */
 SourceBuffer.prototype.dispatchEvent = function(evt) {};
 
 /** @type {string} */
@@ -169,3 +147,9 @@ SourceBuffer.prototype.abort = function() {};
  * @return {undefined}
  */
 SourceBuffer.prototype.remove = function(start, end) {};
+
+/**
+ * @param {string} type
+ * @return {undefined}
+ */
+SourceBuffer.prototype.changeType = function(type) {};
diff --git a/javascript/externs/web/streamsapi.js b/javascript/externs/web/streamsapi.js
index 4a335775aadb..f7d868a573bf 100644
--- a/javascript/externs/web/streamsapi.js
+++ b/javascript/externs/web/streamsapi.js
@@ -24,31 +24,117 @@
  */
 
 
-/** @typedef {{ value:*, done:boolean }} */
-var IteratorResult;
-
-
 /**
  * @typedef {!CountQueuingStrategy|!ByteLengthQueuingStrategy|{
  *     size: (undefined|function(*): number),
- *     highWaterMark: number
+ *     highWaterMark: (number|undefined),
  * }}
  */
 var QueuingStrategy;
 
+/**
+ * The TransformStreamDefaultController class has methods that allow
+ * manipulation of the associated ReadableStream and WritableStream.
+ *
+ * This class cannot be directly constructed and is instead passed by the
+ * TransformStream to the methods of its transformer.
+ *
+ * @interface
+ * @template OUT_VALUE
+ * @see https://streams.spec.whatwg.org/#ts-default-controller-class
+ */
+function TransformStreamDefaultController() {};
+
+/**
+ * @type {number}
+ * @see https://streams.spec.whatwg.org/#ts-default-controller-desired-size
+ */
+TransformStreamDefaultController.prototype.desiredSize;
+
+/**
+ * @param {OUT_VALUE} chunk
+ * @return {undefined}
+ * @see https://streams.spec.whatwg.org/#ts-default-controller-enqueue
+ */
+TransformStreamDefaultController.prototype.enqueue = function(chunk) {};
+
+/**
+ * @param {*} reason
+ * @return {undefined}
+ * @see https://streams.spec.whatwg.org/#ts-default-controller-error
+ */
+TransformStreamDefaultController.prototype.error = function(reason) {};
+
+/**
+ * @return {undefined}
+ * @see https://streams.spec.whatwg.org/#ts-default-controller-terminate
+ */
+TransformStreamDefaultController.prototype.terminate = function() {};
+
+
+/**
+ * @record
+ * @template IN_VALUE, OUT_VALUE
+ * @see https://streams.spec.whatwg.org/#transformer-api
+ */
+function TransformStreamTransformer() {};
+
+/**
+ * @type {(undefined|function(
+ *     !TransformStreamDefaultController<OUT_VALUE>
+ *   ):(!IThenable<*>|undefined)
+ * )}
+ */
+TransformStreamTransformer.prototype.start;
+
+/**
+ * @type {(undefined|function(
+ *     IN_VALUE, !TransformStreamDefaultController<OUT_VALUE>
+ *   ):(!IThenable<*>|undefined)
+ * )}
+ */
+TransformStreamTransformer.prototype.transform;
+
+/**
+ * @type {(undefined|function(
+ *     !TransformStreamDefaultController<OUT_VALUE>
+ *   ):(!IThenable<*>|undefined)
+ * )}
+ */
+TransformStreamTransformer.prototype.flush;
+
 
 /**
+ * A transform stream (https://streams.spec.whatwg.org/#transform-stream).
  * @record
+ * @template IN_VALUE, OUT_VALUE
  */
-function TransformStream() {};
+function ITransformStream() {}
 
-/** @type {!WritableStream} */
+/** @type {!WritableStream<IN_VALUE>} */
+ITransformStream.prototype.writable;
+
+/** @type {!ReadableStream<OUT_VALUE>} */
+ITransformStream.prototype.readable;
+
+
+/**
+ * @constructor
+ * @implements {ITransformStream<IN_VALUE, OUT_VALUE>}
+ * @template IN_VALUE, OUT_VALUE
+ * @param {!TransformStreamTransformer<IN_VALUE, OUT_VALUE>=} transformer
+ * @param {!QueuingStrategy=} writableStrategy
+ * @param {!QueuingStrategy=} readableStrategy
+ * @see https://streams.spec.whatwg.org/#ts-class
+ */
+function TransformStream(transformer, writableStrategy, readableStrategy) {};
+
+/** @type {!WritableStream<IN_VALUE>} */
 TransformStream.prototype.writable;
 
-/** @type {!ReadableStream} */
+/** @type {!ReadableStream<OUT_VALUE>} */
 TransformStream.prototype.readable;
 
-
 /**
  * @record
  */
@@ -66,18 +152,23 @@ PipeOptions.prototype.preventCancel;
 
 /**
  * @record
+ * @template VALUE
  */
 function ReadableStreamSource() {};
 
 /**
- * @type {(undefined|
- *     function((!ReadableByteStreamController|!ReadableStreamDefaultController)):(!IThenable<*>|undefined))}
+ * @type {(undefined|function(
+ *     (!ReadableByteStreamController|!ReadableStreamDefaultController<VALUE>)
+ *   ):(!IThenable<*>|undefined)
+ * )}
  */
 ReadableStreamSource.prototype.start;
 
 /**
- * @type {(undefined|
- *     function((!ReadableByteStreamController|!ReadableStreamDefaultController)):(!IThenable<*>|undefined))}
+ * @type {(undefined|function(
+ *     (!ReadableByteStreamController|!ReadableStreamDefaultController<VALUE>)
+ *   ):(!IThenable<*>|undefined)
+ * )}
  */
 ReadableStreamSource.prototype.pull;
 
@@ -90,11 +181,19 @@ ReadableStreamSource.prototype.type;
 /** @type {(undefined|number)} */
 ReadableStreamSource.prototype.autoAllocateChunkSize;
 
+/**
+ * @record
+ */
+function ReadableStreamIteratorOptions() {};
+
+/** @type {undefined|boolean} */
+ReadableStreamIteratorOptions.prototype.preventCancel;
 
 /**
- * @param {!ReadableStreamSource=} opt_underlyingSource
- * @param {!QueuingStrategy=} opt_queuingStrategy
  * @constructor
+ * @template VALUE
+ * @param {!ReadableStreamSource<VALUE>=} opt_underlyingSource
+ * @param {!QueuingStrategy<VALUE>=} opt_queuingStrategy
  * @see https://streams.spec.whatwg.org/#rs-class
  */
 function ReadableStream(opt_underlyingSource, opt_queuingStrategy) {};
@@ -112,23 +211,31 @@ ReadableStream.prototype.locked;
  */
 ReadableStream.prototype.cancel = function(reason) {};
 
+/**
+ * @param {!ReadableStreamIteratorOptions=} options
+ * @return {!AsyncIterator}
+ * @see https://streams.spec.whatwg.org/#rs-get-iterator
+ */
+ReadableStream.prototype.getIterator = function(options) {};
+
 /**
  * @param {{ mode:(undefined|string) }=} opt_options
- * @return {(!ReadableStreamDefaultReader|!ReadableStreamBYOBReader)}
+ * @return {(!ReadableStreamDefaultReader<VALUE>|!ReadableStreamBYOBReader)}
  * @see https://streams.spec.whatwg.org/#rs-get-reader
  */
 ReadableStream.prototype.getReader = function(opt_options) {};
 
 /**
- * @param {!TransformStream} transform
+ * @template PIPE_VALUE
+ * @param {!ITransformStream<PIPE_VALUE, VALUE>} transform
  * @param {!PipeOptions=} opt_options
- * @return {!ReadableStream}
+ * @return {!ReadableStream<PIPE_VALUE>}
  * @see https://streams.spec.whatwg.org/#rs-pipe-through
  */
 ReadableStream.prototype.pipeThrough = function(transform, opt_options) {};
 
 /**
- * @param {!WritableStream} dest
+ * @param {!WritableStream<VALUE>} dest
  * @param {!PipeOptions=} opt_options
  * @return {!Promise<void>}
  * @see https://streams.spec.whatwg.org/#rs-pipe-to
@@ -136,17 +243,24 @@ ReadableStream.prototype.pipeThrough = function(transform, opt_options) {};
 ReadableStream.prototype.pipeTo = function(dest, opt_options) {};
 
 /**
- * @return {!Array<!ReadableStream>}
+ * @return {!Array<!ReadableStream<VALUE>>}
  * @see https://streams.spec.whatwg.org/#rs-tee
  */
 ReadableStream.prototype.tee = function() {};
 
+/**
+ * @param {!ReadableStreamIteratorOptions=} options
+ * @return {!AsyncIterator}
+ * @see https://streams.spec.whatwg.org/#rs-asynciterator
+ */
+ReadableStream.prototype[Symbol.asyncIterator] = function(options) {};
 
 /**
- * The ReadableStreamDefaultReader constructor is generally not meant to be used directly;
- * instead, a stream’s getReader() method should be used.
+ * The ReadableStreamDefaultReader constructor is generally not meant to be used
+ * directly; instead, a stream’s getReader() method should be used.
  *
  * @interface
+ * @template VALUE
  * @see https://streams.spec.whatwg.org/#default-reader-class
  */
 function ReadableStreamDefaultReader() {};
@@ -165,7 +279,7 @@ ReadableStreamDefaultReader.prototype.closed;
 ReadableStreamDefaultReader.prototype.cancel = function(reason) {};
 
 /**
- * @return {!Promise<!IteratorResult>}
+ * @return {!Promise<!IIterableResult<VALUE>>}
  * @see https://streams.spec.whatwg.org/#default-reader-read
  */
 ReadableStreamDefaultReader.prototype.read = function() {};
@@ -200,8 +314,9 @@ ReadableStreamBYOBReader.prototype.closed;
 ReadableStreamBYOBReader.prototype.cancel = function(reason) {};
 
 /**
- * @param {!ArrayBufferView} view
- * @return {!Promise<!IteratorResult>}
+ * @template BUFFER
+ * @param {BUFFER} view
+ * @return {!Promise<!IIterableResult<BUFFER>>}
  * @see https://streams.spec.whatwg.org/#byob-reader-read
  */
 ReadableStreamBYOBReader.prototype.read = function(view) {};
@@ -218,6 +333,7 @@ ReadableStreamBYOBReader.prototype.releaseLock = function() {};
  * it only works on a ReadableStream that is in the middle of being constructed.
  *
  * @interface
+ * @template VALUE
  * @see https://streams.spec.whatwg.org/#rs-default-controller-class
  */
 function ReadableStreamDefaultController() {};
@@ -235,7 +351,7 @@ ReadableStreamDefaultController.prototype.desiredSize;
 ReadableStreamDefaultController.prototype.close = function() {};
 
 /**
- * @param {*} chunk
+ * @param {VALUE} chunk
  * @return {undefined}
  * @see https://streams.spec.whatwg.org/#rs-default-controller-enqueue
  */
@@ -320,13 +436,17 @@ ReadableStreamBYOBRequest.prototype.respondWithNewView = function(view) {};
 
 /**
  * @record
+ * @template VALUE
  */
 function WritableStreamSink() {};
 
 /** @type {(undefined|function(!WritableStreamDefaultController):(!IThenable<*>|undefined))}*/
 WritableStreamSink.prototype.start;
 
-/** @type {(undefined|function(!WritableStreamDefaultController):(!IThenable<*>|undefined))}*/
+/**
+ * @type {(undefined|function(VALUE,
+ *     !WritableStreamDefaultController):(!IThenable<*>|undefined))}
+ */
 WritableStreamSink.prototype.write;
 
 /** @type {(undefined|function():(!IThenable<*>|undefined))} */
@@ -337,9 +457,10 @@ WritableStreamSink.prototype.abort;
 
 
 /**
- * @param {!WritableStreamSink=} opt_underlyingSink
- * @param {!QueuingStrategy=} opt_queuingStrategy
  * @constructor
+ * @template VALUE
+ * @param {!WritableStreamSink<VALUE>=} opt_underlyingSink
+ * @param {!QueuingStrategy<VALUE>=} opt_queuingStrategy
  * @see https://streams.spec.whatwg.org/#ws-class
  */
 function WritableStream(opt_underlyingSink, opt_queuingStrategy) {};
@@ -358,7 +479,13 @@ WritableStream.prototype.locked;
 WritableStream.prototype.abort = function(reason) {};
 
 /**
- * @return {!WritableStreamDefaultWriter}
+ * @return {!Promise<undefined>}
+ * @see https://streams.spec.whatwg.org/#ws-close
+ */
+WritableStream.prototype.close = function() {};
+
+/**
+ * @return {!WritableStreamDefaultWriter<VALUE>}
  * @see https://streams.spec.whatwg.org/#ws-get-writer
  */
 WritableStream.prototype.getWriter = function() {};
@@ -366,6 +493,7 @@ WritableStream.prototype.getWriter = function() {};
 
 /**
  * @interface
+ * @template VALUE
  * @see https://streams.spec.whatwg.org/#default-writer-class
  */
 function WritableStreamDefaultWriter() {};
@@ -408,7 +536,7 @@ WritableStreamDefaultWriter.prototype.close = function() {};
 WritableStreamDefaultWriter.prototype.releaseLock = function() {};
 
 /**
- * @param {*} chunk
+ * @param {VALUE} chunk
  * @return {!Promise<undefined>}
  * @see https://streams.spec.whatwg.org/#default-writer-write
  */
diff --git a/javascript/externs/web/url.js b/javascript/externs/web/url.js
index c20605fac60b..5566cd5517a0 100644
--- a/javascript/externs/web/url.js
+++ b/javascript/externs/web/url.js
@@ -23,9 +23,32 @@
  */
 
 /**
+ * @typedef {Array<string>}
+ */
+var URLSearchParamsTupleType;
+
+/**
+ * Represents the query string of a URL.
+ *
+ * * When `init` is a string, it is basically parsed as a query string
+ *   `'name1=value1&name2=value2'`.
+ *
+ * * When `init` is an array of arrays of string
+ *   `([['name1', 'value1'], ['name2', 'value2']])`,
+ *   it must contain pairs of strings, where the first item in the pair will be
+ *   interpreted as a key and the second as a value.
+ *
+ *   NOTE: The specification uses Iterable rather than Array, but this is not
+ *   supported in Edge 17 - 18.
+ *
+ * * When `init` is an object, keys and values will be interpreted as such
+ *   `({name1: 'value1', name2: 'value2'}).
+ *
+ * @see https://url.spec.whatwg.org/#interface-urlsearchparams
  * @constructor
  * @implements {Iterable<!Array<string>>}
- * @param {(string|!URLSearchParams)=} init
+ * @param {(string|!Array<!URLSearchParamsTupleType>|!Object<string,string>)=}
+ *     init
  */
 function URLSearchParams(init) {}
 
@@ -42,6 +65,19 @@ URLSearchParams.prototype.append = function(name, value) {};
  */
 URLSearchParams.prototype.delete = function(name) {};
 
+/**
+ * @return {!IteratorIterable<!Array<string>>}
+ * @nosideeffects
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams/entries
+ */
+URLSearchParams.prototype.entries = function() {};
+
+/**
+ * @param {function(string, string)} callback
+ * @return {undefined}
+ */
+URLSearchParams.prototype.forEach = function(callback) {};
+
 /**
  * @param {string} name
  * @return {?string}
@@ -60,6 +96,12 @@ URLSearchParams.prototype.getAll = function(name) {};
  */
 URLSearchParams.prototype.has = function(name) {};
 
+/**
+ * @return {!IteratorIterable<string>}
+ */
+URLSearchParams.prototype.keys = function() {};
+
+
 /**
  * @param {string} name
  * @param {string} value
@@ -67,6 +109,16 @@ URLSearchParams.prototype.has = function(name) {};
  */
 URLSearchParams.prototype.set = function(name, value) {};
 
+/**
+ * @return {undefined}
+ */
+URLSearchParams.prototype.sort = function() {};
+
+/**
+ * @return {!IteratorIterable<string>}
+ */
+URLSearchParams.prototype.values = function() {};
+
 /**
  * @see https://url.spec.whatwg.org
  * @constructor
@@ -79,8 +131,7 @@ function URL(url, base) {}
 URL.prototype.href;
 
 /**
- * @const
- * @type {string}
+ * @const {string}
  */
 URL.prototype.origin;
 
@@ -109,8 +160,7 @@ URL.prototype.pathname;
 URL.prototype.search;
 
 /**
- * @const
- * @type {URLSearchParams}
+ * @const {!URLSearchParams}
  */
 URL.prototype.searchParams;
 
diff --git a/javascript/externs/web/w3c_anim_timing.js b/javascript/externs/web/w3c_anim_timing.js
index 03e0cc2bc91a..78319d4ba562 100644
--- a/javascript/externs/web/w3c_anim_timing.js
+++ b/javascript/externs/web/w3c_anim_timing.js
@@ -23,7 +23,13 @@
  */
 
 /**
- * @param {function(number)} callback
+ * @typedef {function(number): undefined}
+ * @see https://html.spec.whatwg.org/multipage/imagebitmap-and-animations.html#framerequestcallback
+ */
+var FrameRequestCallback;
+
+/**
+ * @param {!FrameRequestCallback} callback
  * @param {Element=} opt_element In early versions of this API, the callback
  *     was invoked only if the element was visible.
  * @return {number}
diff --git a/javascript/externs/web/w3c_batterystatus.js b/javascript/externs/web/w3c_batterystatus.js
index e062cbf2afc4..91eaec58a39e 100644
--- a/javascript/externs/web/w3c_batterystatus.js
+++ b/javascript/externs/web/w3c_batterystatus.js
@@ -17,7 +17,7 @@
 /**
  * @fileoverview Definitions for W3C's Battery Status API.
  *  The whole file has been fully type annotated. Created from
- *  http://www.w3.org/TR/2014/CR-battery-status-20141209/
+ *  https://www.w3.org/TR/battery-status/
  *
  * @externs
  */
@@ -56,24 +56,30 @@ BatteryManager.prototype.level;
 
 
 /**
- * @type {?function(!Event)}
+ * @type {?function(!Event): void}
  */
 BatteryManager.prototype.onchargingchange;
 
 
 /**
- * @type {?function(!Event)}
+ * @type {?function(!Event): void}
  */
 BatteryManager.prototype.onchargingtimechange;
 
 
 /**
- * @type {?function(!Event)}
+ * @type {?function(!Event): void}
  */
 BatteryManager.prototype.ondischargingtimechange;
 
 
 /**
- * @type {?function(!Event)}
+ * @type {?function(!Event): void}
  */
 BatteryManager.prototype.onlevelchange;
+
+/**
+ * @return {!Promise<!BatteryManager>}
+ * @see http://www.w3.org/TR/battery-status/
+ */
+Navigator.prototype.getBattery = function() {};
diff --git a/javascript/externs/web/w3c_css.js b/javascript/externs/web/w3c_css.js
index 5d7eae1acea8..d242d7ab64b6 100644
--- a/javascript/externs/web/w3c_css.js
+++ b/javascript/externs/web/w3c_css.js
@@ -236,52 +236,52 @@ CSSRule.prototype.style;
 
 /**
  * Indicates that the rule is a {@see CSSUnknownRule}.
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSRule-ruleType
  */
-CSSRule.UNKNOWN_RULE = 0;
+CSSRule.UNKNOWN_RULE;
 
 /**
  * Indicates that the rule is a {@see CSSStyleRule}.
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSRule-ruleType
  */
-CSSRule.STYLE_RULE = 1;
+CSSRule.STYLE_RULE;
 
 /**
  * Indicates that the rule is a {@see CSSCharsetRule}.
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSRule-ruleType
  */
-CSSRule.CHARSET_RULE = 2;
+CSSRule.CHARSET_RULE;
 
 /**
  * Indicates that the rule is a {@see CSSImportRule}.
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSRule-ruleType
  */
-CSSRule.IMPORT_RULE = 3;
+CSSRule.IMPORT_RULE;
 
 /**
  * Indicates that the rule is a {@see CSSMediaRule}.
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSRule-ruleType
  */
-CSSRule.MEDIA_RULE = 4;
+CSSRule.MEDIA_RULE;
 
 /**
  * Indicates that the rule is a {@see CSSFontFaceRule}.
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSRule-ruleType
  */
-CSSRule.FONT_FACE_RULE = 5;
+CSSRule.FONT_FACE_RULE;
 
 /**
  * Indicates that the rule is a {@see CSSPageRule}.
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSRule-ruleType
  */
-CSSRule.PAGE_RULE = 6;
+CSSRule.PAGE_RULE;
 
 /**
  * @constructor
@@ -418,6 +418,7 @@ function CSSUnknownRule() {}
  * @extends {CSSProperties}
  * @implements {IObject<(string|number), string>}
  * @implements {IArrayLike<string>}
+ * @implements {Iterable<string>}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSStyleDeclaration
  */
 function CSSStyleDeclaration() {}
@@ -518,6 +519,7 @@ CSSStyleDeclaration.prototype.removeAttribute =
 CSSStyleDeclaration.prototype.removeExpression = function(name) {};
 
 /**
+ * @deprecated
  * @param {string} name
  * @param {*} value
  * @param {number=} opt_flags
@@ -556,28 +558,28 @@ CSSValue.prototype.cssText;
 CSSValue.prototype.cssValueType;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSValue-types
  */
-CSSValue.CSS_INHERIT = 0;
+CSSValue.CSS_INHERIT;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSValue-types
  */
-CSSValue.CSS_PRIMITIVE_VALUE = 1;
+CSSValue.CSS_PRIMITIVE_VALUE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSValue-types
  */
-CSSValue.CSS_VALUE_LIST = 2;
+CSSValue.CSS_VALUE_LIST;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSValue-types
  */
-CSSValue.CSS_CUSTOM = 3;
+CSSValue.CSS_CUSTOM;
 
 /**
  * @constructor
@@ -593,160 +595,160 @@ function CSSPrimitiveValue() {}
 CSSPrimitiveValue.prototype.primitiveType;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_UNKNOWN = 0;
+CSSPrimitiveValue.CSS_UNKNOWN;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_NUMBER = 1;
+CSSPrimitiveValue.CSS_NUMBER;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_PERCENTAGE = 2;
+CSSPrimitiveValue.CSS_PERCENTAGE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_EMS = 3;
+CSSPrimitiveValue.CSS_EMS;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_EXS = 4;
+CSSPrimitiveValue.CSS_EXS;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_PX = 5;
+CSSPrimitiveValue.CSS_PX;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_CM = 6;
+CSSPrimitiveValue.CSS_CM;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_MM = 7;
+CSSPrimitiveValue.CSS_MM;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_IN = 8;
+CSSPrimitiveValue.CSS_IN;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_PT = 9;
+CSSPrimitiveValue.CSS_PT;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_PC = 10;
+CSSPrimitiveValue.CSS_PC;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_DEG = 11;
+CSSPrimitiveValue.CSS_DEG;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_RAD = 12;
+CSSPrimitiveValue.CSS_RAD;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_GRAD = 13;
+CSSPrimitiveValue.CSS_GRAD;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_MS = 14;
+CSSPrimitiveValue.CSS_MS;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_S = 15;
+CSSPrimitiveValue.CSS_S;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_HZ = 16;
+CSSPrimitiveValue.CSS_HZ;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_KHZ = 17;
+CSSPrimitiveValue.CSS_KHZ;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_DIMENSION = 18;
+CSSPrimitiveValue.CSS_DIMENSION;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_STRING = 19;
+CSSPrimitiveValue.CSS_STRING;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_URI = 20;
+CSSPrimitiveValue.CSS_URI;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_IDENT = 21;
+CSSPrimitiveValue.CSS_IDENT;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_ATTR = 22;
+CSSPrimitiveValue.CSS_ATTR;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_COUNTER = 23;
+CSSPrimitiveValue.CSS_COUNTER;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_RECT = 24;
+CSSPrimitiveValue.CSS_RECT;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSPrimitiveValue
  */
-CSSPrimitiveValue.CSS_RGBCOLOR = 25;
+CSSPrimitiveValue.CSS_RGBCOLOR;
 
 /**
  * @return {Counter}
@@ -904,7 +906,7 @@ Counter.prototype.listStyle;
 Counter.prototype.separator;
 
 /**
- * @constructor
+ * @interface
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-ViewCSS
  */
 function ViewCSS() {}
@@ -975,6 +977,12 @@ function CSSProperties() {}
  */
 CSSProperties.prototype.azimuth;
 
+/**
+ * @type {string}
+ * @see https://drafts.fxtf.org/filter-effects-2/#BackdropFilterProperty
+ */
+CSSProperties.prototype.backdropFilter;
+
 /**
  * @type {string}
  * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSProperties-background
@@ -1820,6 +1828,62 @@ CSSProperties.prototype.opacity;
  */
 CSSProperties.prototype.textOverflow;
 
+// CSS 3 animations
+
+/**
+ * @type {string|number}
+ * @see https://www.w3.org/TR/css-animations-1/#animation
+ */
+CSSProperties.prototype.animation;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/css-animations-1/#animation-delay
+ */
+CSSProperties.prototype.animationDelay;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/css-animations-1/#animation-direction
+ */
+CSSProperties.prototype.animationDirection;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/css-animations-1/#animation-duration
+ */
+CSSProperties.prototype.animationDuration;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/css-animations-1/#animation-fill-mode
+ */
+CSSProperties.prototype.animationFillMode;
+
+/**
+ * @type {string|number}
+ * @see https://www.w3.org/TR/css-animations-1/#animation-iteration-count
+ */
+CSSProperties.prototype.animationIterationCount;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/css-animations-1/#animation-name
+ */
+CSSProperties.prototype.animationName;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/css-animations-1/#animation-play-state
+ */
+CSSProperties.prototype.animationPlayState;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/css-animations-1/#animation-timing-function
+ */
+CSSProperties.prototype.animationTimingFunction;
+
 // CSS 3 transforms
 
 /**
@@ -1981,6 +2045,129 @@ CSSProperties.prototype.order;
  */
 CSSProperties.prototype.willChange;
 
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/css-ui-4/#propdef-user-select
+ */
+CSSProperties.prototype.userSelect;
+
+// CSS 3 Images
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/css3-images/#the-object-fit
+ */
+CSSProperties.prototype.objectFit;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/css3-images/#object-position
+ */
+CSSProperties.prototype.objectPosition;
+
+// CSS Masking
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/css-masking-1/
+ */
+CSSProperties.prototype.clipPath;
+
+// CSS Containment
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/css-contain-1/
+ */
+CSSProperties.prototype.contain;
+
+// SVG Fill Properties
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/fill-stroke-3/#fill-shorthand
+ */
+CSSProperties.prototype.fill;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/fill-stroke-3/#fill-opacity
+ */
+CSSProperties.prototype.fillOpacity;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/fill-stroke-3/#fill-rule
+ */
+CSSProperties.prototype.fillRule;
+
+// SVG Stroke Properties
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/svg-strokes/
+ */
+CSSProperties.prototype.stroke;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/svg-strokes/
+ */
+CSSProperties.prototype.strokeAlignment;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/svg-strokes/
+ */
+CSSProperties.prototype.strokeOpacity;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/svg-strokes/
+ */
+CSSProperties.prototype.strokeWidth;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/svg-strokes/
+ */
+CSSProperties.prototype.strokeLinecap;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/svg-strokes/
+ */
+CSSProperties.prototype.strokeLinejoin;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/svg-strokes/
+ */
+CSSProperties.prototype.strokeMiterlimit;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/svg-strokes/
+ */
+CSSProperties.prototype.strokeDasharray;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/svg-strokes/
+ */
+CSSProperties.prototype.strokeDashoffset;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/svg-strokes/
+ */
+CSSProperties.prototype.strokeDashcorner;
+
+/**
+ * @type {string}
+ * @see https://www.w3.org/TR/svg-strokes/
+ */
+CSSProperties.prototype.strokeDashadjust;
 
 /**
  * TODO(dbeam): Put this in separate file named w3c_cssom.js.
@@ -1992,7 +2179,7 @@ CSSProperties.prototype.willChange;
 
 /**
  * @param {string} media_query_list
- * @return {MediaQueryList}
+ * @return {!MediaQueryList}
  * @see http://www.w3.org/TR/cssom-view/#dom-window-matchmedia
  */
 Window.prototype.matchMedia = function(media_query_list) {};
@@ -2034,28 +2221,53 @@ Window.prototype.scrollY;
 Window.prototype.pageYOffset;
 
 /**
- * @param {number} x
- * @param {number} y
+ * @typedef {{
+ *   left: (number|undefined),
+ *   top: (number|undefined),
+ *   behavior: (string|undefined)
+ * }}
+ * @see https://www.w3.org/TR/cssom-view/#dictdef-scrolltooptions
+ */
+var ScrollToOptions;
+
+/**
+ * @record
+ * @see https://www.w3.org/TR/cssom-view/#dictdef-scrollintoviewoptions
+ */
+function ScrollIntoViewOptions () {}
+
+/** @type {string|undefined} */
+ScrollIntoViewOptions.prototype.behavior;
+
+/** @type {string|undefined} */
+ScrollIntoViewOptions.prototype.block;
+
+/** @type {string|undefined} */
+ScrollIntoViewOptions.prototype.inline;
+
+/**
+ * @param {number|!ScrollToOptions} scrollToOptionsOrX
+ * @param {number=} opt_y
  * @see http://www.w3.org/TR/cssom-view/#dom-window-scroll
  * @return {undefined}
  */
-Window.prototype.scroll = function(x, y) {};
+Window.prototype.scroll = function(scrollToOptionsOrX, opt_y) {};
 
 /**
- * @param {number} x
- * @param {number} y
+ * @param {number|!ScrollToOptions} scrollToOptionsOrX
+ * @param {number=} opt_y
  * @see http://www.w3.org/TR/cssom-view/#dom-window-scrollto
  * @return {undefined}
  */
-Window.prototype.scrollTo = function(x, y) {};
+Window.prototype.scrollTo = function(scrollToOptionsOrX, opt_y) {};
 
 /**
- * @param {number} x
- * @param {number} y
+ * @param {number|!ScrollToOptions} scrollToOptionsOrX
+ * @param {number=} opt_y
  * @see http://www.w3.org/TR/cssom-view/#dom-window-scrollby
  * @return {undefined}
  */
-Window.prototype.scrollBy = function(x, y) {};
+Window.prototype.scrollBy = function(scrollToOptionsOrX, opt_y) {};
 
 /**
  * @type {number}
@@ -2081,8 +2293,47 @@ Window.prototype.outerWidth;
  */
 Window.prototype.outerHeight;
 
+/**
+ * @type {number}
+ * @see https://www.w3.org/TR/cssom-view/#dom-window-devicepixelratio
+ */
+Window.prototype.devicePixelRatio;
+
+/**
+ * @param {number} x
+ * @param {number} y
+ * @return {undefined}
+ * @see https://www.w3.org/TR/cssom-view/#dom-window-moveto
+ */
+Window.prototype.moveTo = function(x, y) {};
+
+/**
+ * @param {number} x
+ * @param {number} y
+ * @return {undefined}
+ * @see https://www.w3.org/TR/cssom-view/#dom-window-moveby
+ */
+Window.prototype.moveBy = function(x, y) {};
+
+/**
+ * @param {number} x
+ * @param {number} y
+ * @return {undefined}
+ * @see https://www.w3.org/TR/cssom-view/#dom-window-resizeto
+ */
+Window.prototype.resizeTo = function(x, y) {};
+
+/**
+ * @param {number} x
+ * @param {number} y
+ * @return {undefined}
+ * @see https://www.w3.org/TR/cssom-view/#dom-window-resizeby
+ */
+Window.prototype.resizeBy = function(x, y) {};
+
 /**
  * @constructor
+ * @implements {EventTarget}
  * @see http://www.w3.org/TR/cssom-view/#mediaquerylist
  */
 function MediaQueryList() {}
@@ -2113,6 +2364,17 @@ MediaQueryList.prototype.addListener = function(listener) {};
  */
 MediaQueryList.prototype.removeListener = function(listener) {};
 
+/** @override Not available in some browsers; use addListener instead. */
+MediaQueryList.prototype.addEventListener = function(
+    type, listener, opt_options) {};
+
+/** @override Not available in old browsers; use removeListener instead. */
+MediaQueryList.prototype.removeEventListener = function(
+    type, listener, opt_options) {};
+
+/** @override */
+MediaQueryList.prototype.dispatchEvent = function(evt) {};
+
 /**
  * @typedef {(function(!MediaQueryList) : void)}
  * @see http://www.w3.org/TR/cssom-view/#mediaquerylistlistener
@@ -2172,6 +2434,14 @@ Screen.prototype.pixelDepth;
  */
 Document.prototype.elementFromPoint = function(x, y) {};
 
+/**
+ * @param {number} x
+ * @param {number} y
+ * @return {!IArrayLike<!Element>}
+ * @see http://www.w3.org/TR/cssom-view/#dom-document-elementsfrompoint
+ */
+Document.prototype.elementsFromPoint = function(x, y) {};
+
 /**
  * @param {number} x
  * @param {number} y
@@ -2214,17 +2484,25 @@ CaretPosition.prototype.offset;
 Element.prototype.getClientRects = function() {};
 
 /**
- * @return {!ClientRect}
+ * @return {!DOMRect}
  * @see http://www.w3.org/TR/cssom-view/#dom-element-getboundingclientrect
  */
 Element.prototype.getBoundingClientRect = function() {};
 
 /**
- * @param {(boolean|{behavior: string, block: string})=} opt_top
+ * @param {(boolean|ScrollIntoViewOptions)=} top
  * @see http://www.w3.org/TR/cssom-view/#dom-element-scrollintoview
  * @return {undefined}
  */
-Element.prototype.scrollIntoView = function(opt_top) {};
+Element.prototype.scrollIntoView = function(top) {};
+
+/**
+ * @param {number|!ScrollToOptions} scrollToOptionsOrX
+ * @param {number=} opt_y
+ * @see https://www.w3.org/TR/cssom-view/#extension-to-the-element-interface
+ * @return {undefined}
+ */
+Element.prototype.scrollTo = function(scrollToOptionsOrX, opt_y) {};
 
 /**
  * @type {number}
@@ -2316,7 +2594,7 @@ HTMLElement.prototype.offsetHeight;
 Range.prototype.getClientRects = function() {};
 
 /**
- * @return {!ClientRect}
+ * @return {!DOMRect}
  * @see http://www.w3.org/TR/cssom-view/#dom-range-getboundingclientrect
  */
 Range.prototype.getBoundingClientRect = function() {};
@@ -2395,7 +2673,7 @@ MouseEvent.prototype.offsetY;
 /**
  * @constructor
  * @see http://www.w3.org/TR/cssom-view/#the-clientrectlist-interface
- * @implements {IArrayLike<!ClientRect>}
+ * @implements {IArrayLike<!DOMRect>}
  */
 function ClientRectList() {}
 
@@ -2407,53 +2685,11 @@ ClientRectList.prototype.length;
 
 /**
  * @param {number} index
- * @return {ClientRect}
+ * @return {?DOMRect}
  * @see http://www.w3.org/TR/cssom-view/#dom-clientrectlist-item
  */
 ClientRectList.prototype.item = function(index) {};
 
-/**
- * @constructor
- * @see http://www.w3.org/TR/cssom-view/#the-clientrect-interface
- */
-function ClientRect() {}
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/cssom-view/#dom-clientrect-top
- */
-ClientRect.prototype.top;
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/cssom-view/#dom-clientrect-right
- */
-ClientRect.prototype.right;
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/cssom-view/#dom-clientrect-bottom
- */
-ClientRect.prototype.bottom;
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/cssom-view/#dom-clientrect-left
- */
-ClientRect.prototype.left;
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/cssom-view/#dom-clientrect-width
- */
-ClientRect.prototype.width;
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/cssom-view/#dom-clientrect-height
- */
-ClientRect.prototype.height;
-
 /**
  * @constructor
  * http://www.w3.org/TR/css3-conditional/#CSS-interface
@@ -2620,12 +2856,12 @@ FontFaceSet.prototype.delete = function(value) {};
 FontFaceSet.prototype.has = function(font) {};
 
 /**
- * @param {function(!FontFace, number, !FontFaceSet)} cb
- * @param {Object|undefined=} opt_selfObj
+ * @param {function(!FontFace, number, !FontFaceSet)} callback
+ * @param {?Object=} selfObj
  * see http://dev.w3.org/csswg/css-font-loading/#dom-fontfaceset-foreach
  * @return {undefined}
  */
-FontFaceSet.prototype.forEach = function(cb, opt_selfObj) {};
+FontFaceSet.prototype.forEach = function(callback, selfObj) {};
 
 /**
  * @param {string} font
@@ -2654,3 +2890,92 @@ FontFaceSet.prototype.ready;
  * @see http://dev.w3.org/csswg/css-font-loading/#dom-fontfaceset-status
  */
 FontFaceSet.prototype.status;
+
+/**
+ * @constructor
+ * @param {string} type
+ * @param {{
+ *   animationName: (string|undefined),
+ *   elapsedTime: (number|undefined),
+ *   pseudoElement: (string|undefined)
+ * }=} opt_animationEventInitDict
+ * @extends {Event}
+ * @see https://drafts.csswg.org/css-animations/#interface-animationevent
+ */
+function AnimationEvent(type, opt_animationEventInitDict) {};
+
+/**
+ * @type {string}
+ * @see https://drafts.csswg.org/css-animations/#dom-animationevent-animationname
+ */
+AnimationEvent.prototype.animationName;
+
+/**
+ * @type {number}
+ * @see https://drafts.csswg.org/css-animations/#dom-animationevent-elapsedtime
+ */
+AnimationEvent.prototype.elapsedTime;
+
+/**
+ * @type {string}
+ * @see https://drafts.csswg.org/css-animations/#dom-animationevent-pseudoelement
+ */
+AnimationEvent.prototype.pseudoElement;
+
+/**
+ * @constructor
+ * @extends {CSSRule}
+ * @see http://dev.w3.org/csswg/css-animations/#csskeyframerule
+ */
+function CSSKeyframeRule() {}
+
+/**
+ * @type {string}
+ * @see https://drafts.csswg.org/css-animations/#dom-csskeyframerule-keytext
+ */
+CSSKeyframeRule.prototype.keyText;
+
+/**
+ * @type {!CSSStyleDeclaration}
+ * @see https://drafts.csswg.org/css-animations/#dom-csskeyframerule-style
+ */
+CSSKeyframeRule.prototype.style;
+
+
+/**
+ * @constructor
+ * @extends {CSSRule}
+ * @see http://dev.w3.org/csswg/css-animations/#csskeyframesrule
+ */
+function CSSKeyframesRule() {}
+
+/**
+ * @see https://drafts.csswg.org/css-animations/#dom-csskeyframesrule-name
+ * @type {string}
+ */
+CSSKeyframesRule.prototype.name;
+
+/**
+ * @see https://drafts.csswg.org/css-animations/#dom-csskeyframesrule-cssrules
+ * @type {!CSSRuleList}
+ */
+CSSKeyframesRule.prototype.cssRules;
+
+/**
+ * @see https://drafts.csswg.org/css-animations/#dom-csskeyframesrule-findrule
+ * @param {string} key The key text for the rule to find.
+ * @return {?CSSKeyframeRule}
+ */
+CSSKeyframesRule.prototype.findRule = function(key) {};
+
+/**
+ * @see https://drafts.csswg.org/css-animations/#dom-csskeyframesrule-appendrule
+ * @param {string} rule The text for the rule to append.
+ */
+CSSKeyframesRule.prototype.appendRule = function(rule) {};
+
+/**
+ * @see https://drafts.csswg.org/css-animations/#dom-csskeyframesrule-deleterule
+ * @param {string} key The key text for the rule to delete.
+ */
+CSSKeyframesRule.prototype.deleteRule = function(key) {};
diff --git a/javascript/externs/web/w3c_device_sensor_event.js b/javascript/externs/web/w3c_device_sensor_event.js
index de36ea324484..98789d265afb 100644
--- a/javascript/externs/web/w3c_device_sensor_event.js
+++ b/javascript/externs/web/w3c_device_sensor_event.js
@@ -24,11 +24,32 @@
  * @externs
  */
 
+/**
+ * @record
+ * @extends {EventInit}
+ * @see https://w3c.github.io/deviceorientation/spec-source-orientation.html#deviceorientation
+ */
+function DeviceOrientationEventInit() {}
+
+/** @type {number|undefined} */
+DeviceOrientationEventInit.prototype.alpha;
+
+/** @type {number|undefined} */
+DeviceOrientationEventInit.prototype.beta;
+
+/** @type {number|undefined} */
+DeviceOrientationEventInit.prototype.gamma;
+
+/** @type {boolean|undefined} */
+DeviceOrientationEventInit.prototype.absolute;
+
 /**
  * @constructor
  * @extends {Event}
+ * @param {string} type
+ * @param {!DeviceOrientationEventInit=} opt_eventInitDict
  */
-function DeviceOrientationEvent() {}
+function DeviceOrientationEvent(type, opt_eventInitDict) {}
 
 /** @type {?number} */
 DeviceOrientationEvent.prototype.alpha;
diff --git a/javascript/externs/web/w3c_dom1.js b/javascript/externs/web/w3c_dom1.js
index bf85793fec6b..cb0537cefed0 100644
--- a/javascript/externs/web/w3c_dom1.js
+++ b/javascript/externs/web/w3c_dom1.js
@@ -20,76 +20,75 @@
  *  http://www.w3.org/TR/REC-DOM-Level-1/ecma-script-language-binding.html
  *
  * @externs
- * @author stevey@google.com (Steve Yegge)
  */
 
 /**
  * @constructor
  * @param {string=} message
- * @param {string=} message
- * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-17189187
+ * @param {string=} name
+ * @see https://heycam.github.io/webidl/#idl-DOMException
  */
 function DOMException(message, name) {}
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-258A00AF
  */
-DOMException.INDEX_SIZE_ERR = 1;
+DOMException.INDEX_SIZE_ERR;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-258A00AF
  */
-DOMException.DOMSTRING_SIZE_ERR = 2;
+DOMException.DOMSTRING_SIZE_ERR;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-258A00AF
  */
-DOMException.HIERARCHY_REQUEST_ERR = 3;
+DOMException.HIERARCHY_REQUEST_ERR;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-258A00AF
  */
-DOMException.WRONG_DOCUMENT_ERR = 4;
+DOMException.WRONG_DOCUMENT_ERR;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-258A00AF
  */
-DOMException.INVALID_CHARACTER_ERR = 5;
+DOMException.INVALID_CHARACTER_ERR;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-258A00AF
  */
-DOMException.NO_DATA_ALLOWED_ERR = 6;
+DOMException.NO_DATA_ALLOWED_ERR;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-258A00AF
  */
-DOMException.NO_MODIFICATION_ALLOWED_ERR = 7;
+DOMException.NO_MODIFICATION_ALLOWED_ERR;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-258A00AF
  */
-DOMException.NOT_FOUND_ERR = 8;
+DOMException.NOT_FOUND_ERR;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-258A00AF
  */
-DOMException.NOT_SUPPORTED_ERR = 9;
+DOMException.NOT_SUPPORTED_ERR;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-258A00AF
  */
-DOMException.INUSE_ATTRIBUTE_ERR = 10;
+DOMException.INUSE_ATTRIBUTE_ERR;
 
 /**
  * @constructor
@@ -119,24 +118,13 @@ DOMImplementation.prototype.hasFeature = function(feature, version) {};
  */
 function Node() {}
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-Node.prototype.addEventListener = function(type, listener, opt_useCapture) {};
+/** @override */
+Node.prototype.addEventListener = function(type, listener, opt_options) {};
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-Node.prototype.removeEventListener = function(type, listener, opt_useCapture) {};
+/** @override */
+Node.prototype.removeEventListener = function(type, listener, opt_options) {};
 
-/**
- * @override
- * @return {boolean}
- */
+/** @override */
 Node.prototype.dispatchEvent = function(evt) {};
 
 /**
@@ -207,14 +195,16 @@ Node.prototype.previousSibling;
 
 /**
  * @param {Node} newChild
- * @return {Node}
+ * @return {!Node}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#method-appendChild
  */
 Node.prototype.appendChild = function(newChild) {};
 
 /**
  * @param {boolean} deep
- * @return {!Node}
+ * @return {THIS}
+ * @this {THIS}
+ * @template THIS
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#method-cloneNode
  * @nosideeffects
  */
@@ -251,79 +241,73 @@ Node.prototype.removeChild = function(oldChild) {};
 Node.prototype.replaceChild = function(newChild, oldChild) {};
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-1950641247
  */
 Node.ATTRIBUTE_NODE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-1950641247
  */
 Node.CDATA_SECTION_NODE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-1950641247
  */
 Node.COMMENT_NODE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-1950641247
  */
 Node.DOCUMENT_FRAGMENT_NODE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-1950641247
  */
 Node.DOCUMENT_NODE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-1950641247
  */
 Node.DOCUMENT_TYPE_NODE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-1950641247
  */
 Node.ELEMENT_NODE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-1950641247
  */
 Node.ENTITY_NODE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-1950641247
  */
 Node.ENTITY_REFERENCE_NODE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-1950641247
  */
 Node.PROCESSING_INSTRUCTION_NODE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-1950641247
  */
 Node.TEXT_NODE;
 
 /**
- * @type {number}
- * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-1950641247
- */
-Node.XPATH_NAMESPACE_NODE;
-
-/**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-1950641247
  */
 Node.NOTATION_NODE;
@@ -349,7 +333,7 @@ function Document() {}
 Document.prototype.doctype;
 
 /**
- * @type {!Element}
+ * @type {!HTMLHtmlElement}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#attribute-documentElement
  */
 Document.prototype.documentElement;
@@ -395,25 +379,17 @@ Document.prototype.createDocumentFragment = function() {};
  * Create a DOM element.
  *
  * Web components introduced the second parameter as a way of extending existing
- * tags (e.g. document.createElement('button', 'fancy-button')).
+ * tags (e.g. document.createElement('button', {is: 'fancy-button'})).
  *
  * @param {string} tagName
- * @param {string=} opt_typeExtension
+ * @param {({is: string}|string)=} opt_typeExtension
  * @return {!Element}
  * @nosideeffects
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#method-createElement
- * @see http://w3c.github.io/webcomponents/spec/custom/#extensions-to-document-interface-to-instantiate
+ * @see https://dom.spec.whatwg.org/#dom-document-createelement
  */
 Document.prototype.createElement = function(tagName, opt_typeExtension) {};
 
-/**
- * @param {string} name
- * @return {!EntityReference}
- * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#method-createEntityReference
- * @nosideeffects
- */
-Document.prototype.createEntityReference = function(name) {};
-
 /**
  * @param {string} target
  * @param {string} data
@@ -439,6 +415,32 @@ Document.prototype.createTextNode = function(data) {};
  */
 Document.prototype.getElementsByTagName = function(tagname) {};
 
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/Document/open
+ * @see https://html.spec.whatwg.org/multipage/dynamic-markup-insertion.html#dom-document-open
+ */
+Document.prototype.open;
+
+/**
+ * @return {undefined}
+ * @see https://html.spec.whatwg.org/multipage/dynamic-markup-insertion.html#dom-document-close
+ */
+Document.prototype.close = function() {};
+
+/**
+ * @param {!TrustedHTML|string} text
+ * @return {undefined}
+ * @see https://html.spec.whatwg.org/multipage/dynamic-markup-insertion.html#dom-document-write
+ */
+Document.prototype.write = function(text) {};
+
+/**
+ * @param {!TrustedHTML|string} text
+ * @return {undefined}
+ * @see https://html.spec.whatwg.org/multipage/dynamic-markup-insertion.html#dom-document-writeln
+ */
+Document.prototype.writeln = function(text) {};
+
 /**
  * @constructor
  * @implements {IArrayLike<T>}
@@ -461,6 +463,33 @@ NodeList.prototype.length;
  */
 NodeList.prototype.item = function(index) {};
 
+/**
+ * @param {?function(this:S, T, number, !NodeList<T>): ?} callback
+ * @param {S=} opt_thisobj
+ * @template S
+ * @return {undefined}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/NodeList/forEach
+ */
+NodeList.prototype.forEach = function(callback, opt_thisobj) {};
+
+/**
+ * @return {!IteratorIterable<!Array<number|T>>}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/NodeList/entries
+ */
+NodeList.prototype.entries = function() {};
+
+/**
+ * @return {!IteratorIterable<number>}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/NodeList/keys
+ */
+NodeList.prototype.keys = function() {};
+
+/**
+ * @return {!IteratorIterable<T>}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/NodeList/values
+ */
+NodeList.prototype.values = function() {};
+
 /**
  * @constructor
  * @implements {IObject<(string|number), T>}
@@ -599,6 +628,13 @@ Attr.prototype.value;
  */
 function Element() {}
 
+/**
+ * @type {string}
+ * @implicitCast
+ * @see https://dom.spec.whatwg.org/index.html#dom-element-id
+ */
+Element.prototype.id;
+
 /**
  * An Element always contains a non-null NamedNodeMap containing the attributes
  * of this node.
@@ -626,13 +662,13 @@ Element.prototype.className;
 
 /**
  * @param {string} name
- * @param {number?=} opt_flags
+ * @param {?number=} flags
  * @return {string}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#method-getAttribute
  * @see http://msdn.microsoft.com/en-us/library/ms536429(VS.85).aspx
  * @nosideeffects
  */
-Element.prototype.getAttribute = function(name, opt_flags) {};
+Element.prototype.getAttribute = function(name, flags) {};
 
 /**
  * @param {string} name
@@ -666,9 +702,9 @@ Element.prototype.removeAttributeNode = function(oldAttr) {};
 
 /**
  * @param {string} name
- * @param {string|number|boolean} value Values are converted to strings with
- *     ToString, so we accept number and boolean since both convert easily to
- *     strings.
+ * @param {string|number|boolean|!TrustedHTML|!TrustedScriptURL}
+ *     value Values are converted to strings with ToString, so we accept number
+ *     and boolean since both convert easily to strings.
  * @return {undefined}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#method-setAttribute
  */
@@ -706,8 +742,8 @@ Element.prototype.setAttributeNode = function(newAttr) {};
 /** @type {?function (Event)} */ Element.prototype.onkeydown;
 /** @type {?function (Event)} */ Element.prototype.onkeypress;
 /** @type {?function (Event)} */ Element.prototype.onkeyup;
-/** @type {?function (Event)} */ Element.prototype.onload;
-/** @type {?function (Event)} */ Element.prototype.onunload;
+/** @type {?function (Event): void} */ Element.prototype.onload;
+/** @type {?function (Event): void} */ Element.prototype.onunload;
 /** @type {?function (Event)} */ Element.prototype.onmousedown;
 /** @type {?function (Event)} */ Element.prototype.onmousemove;
 /** @type {?function (Event)} */ Element.prototype.onmouseout;
@@ -726,9 +762,10 @@ Element.prototype.setAttributeNode = function(newAttr) {};
 /**
  * @constructor
  * @extends {CharacterData}
+ * @param {string=} contents Optional textual content.
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-1312295772
  */
-function Text() {}
+function Text(contents) {}
 
 /**
  * @param {number} offset
@@ -758,75 +795,12 @@ function CDATASection() {}
  */
 function DocumentType() {}
 
-/**
- * @type {NamedNodeMap<!Entity>}
- * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-1788794630
- */
-DocumentType.prototype.entities;
-
 /**
  * @type {string}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-1844763134
  */
 DocumentType.prototype.name;
 
-/**
- * @type {NamedNodeMap<!Notation>}
- * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-D46829EF
- */
-DocumentType.prototype.notations;
-
-/**
- * @constructor
- * @extends {Node}
- * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-5431D1B9
- */
-function Notation() {}
-
-/**
- * @type {string}
- * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-54F2B4D0
- */
-Notation.prototype.publicId;
-
-/**
- * @type {string}
- * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-E8AAB1D0
- */
-Notation.prototype.systemId;
-
-/**
- * @constructor
- * @extends {Node}
- * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-527DCFF2
- */
-function Entity() {}
-
-/**
- * @type {string}
- * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-D7303025
- */
-Entity.prototype.publicId;
-
-/**
- * @type {string}
- * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-D7C29F3E
- */
-Entity.prototype.systemId;
-
-/**
- * @type {string}
- * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-6ABAEB38
- */
-Entity.prototype.notationName;
-
-/**
- * @constructor
- * @extends {Node}
- * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#ID-11C98490
- */
-function EntityReference() {}
-
 /**
  * @constructor
  * @extends {Node}
@@ -854,25 +828,13 @@ ProcessingInstruction.prototype.target;
 function Window() {}
 Window.prototype.Window;
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-Window.prototype.addEventListener = function(type, listener, opt_useCapture) {};
+/** @override */
+Window.prototype.addEventListener = function(type, listener, opt_options) {};
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-Window.prototype.removeEventListener = function(type, listener, opt_useCapture)
-    {};
+/** @override */
+Window.prototype.removeEventListener = function(type, listener, opt_options) {};
 
-/**
- * @override
- * @return {boolean}
- */
+/** @override */
 Window.prototype.dispatchEvent = function(evt) {};
 
 /** @type {?function (Event)} */ Window.prototype.onabort;
@@ -885,9 +847,11 @@ Window.prototype.dispatchEvent = function(evt) {};
 /** @type {?function (Event)} */ Window.prototype.ondblclick;
 /** @type {?function (Event)} */ Window.prototype.ondragdrop;
 // onerror has a special signature.
-// See https://developer.mozilla.org/en/DOM/window.onerror
-// and http://msdn.microsoft.com/en-us/library/cc197053(VS.85).aspx
-/** @type {?function (string, string, number)} */
+// See
+//  https://developer.mozilla.org/en-US/docs/Web/API/GlobalEventHandlers/onerror
+/**
+ * @type {?function (string, string, number, number, !Error):?}
+ */
 Window.prototype.onerror;
 /** @type {?function (Event)} */ Window.prototype.onfocus;
 /** @type {?function (Event)} */ Window.prototype.onhashchange;
@@ -908,5 +872,7 @@ Window.prototype.onerror;
 /** @type {?function (Event)} */ Window.prototype.onscroll;
 /** @type {?function (Event)} */ Window.prototype.onselect;
 /** @type {?function (Event=)} */ Window.prototype.onsubmit;
+/** @type {?function (Event)} */ Window.prototype.onunhandledrejection;
 /** @type {?function (Event)} */ Window.prototype.onunload;
 /** @type {?function (Event)} */ Window.prototype.onwheel;
+/** @type {?function (Event)} */ Window.prototype.onstorage;
diff --git a/javascript/externs/web/w3c_dom2.js b/javascript/externs/web/w3c_dom2.js
index fa35250d79fb..43867eff7b84 100644
--- a/javascript/externs/web/w3c_dom2.js
+++ b/javascript/externs/web/w3c_dom2.js
@@ -51,6 +51,32 @@ Document.prototype.createElementNS =
 Document.prototype.createAttributeNS =
     function(namespaceURI, qualifiedName) {};
 
+/**
+ * @param {Node} root
+ * @param {number=} whatToShow
+ * @param {NodeFilter=} filter
+ * @param {boolean=} entityReferenceExpansion
+ * @return {!NodeIterator}
+ * @see https://www.w3.org/TR/2000/REC-DOM-Level-2-Traversal-Range-20001113/traversal.html#Traversal-Document
+ * @see https://dom.spec.whatwg.org/#interface-document
+ * @nosideeffects
+ */
+Document.prototype.createNodeIterator = function(
+    root, whatToShow, filter, entityReferenceExpansion) {};
+
+/**
+ * @param {Node} root
+ * @param {number=} whatToShow
+ * @param {NodeFilter=} filter
+ * @param {boolean=} entityReferenceExpansion
+ * @return {!TreeWalker}
+ * @see https://www.w3.org/TR/2000/REC-DOM-Level-2-Traversal-Range-20001113/traversal.html#Traversal-Document
+ * @see https://dom.spec.whatwg.org/#interface-document
+ * @nosideeffects
+ */
+Document.prototype.createTreeWalker = function(
+    root, whatToShow, filter, entityReferenceExpansion) {};
+
 /**
  * @param {string} namespace
  * @param {string} name
@@ -61,9 +87,9 @@ Document.prototype.createAttributeNS =
 Document.prototype.getElementsByTagNameNS = function(namespace, name) {};
 
 /**
- * @param {Node} externalNode
- * @param {boolean} deep
- * @return {Node}
+ * @param {!Node} externalNode
+ * @param {boolean=} deep
+ * @return {!Node}
  * @see https://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/core.html#Core-Document-importNode
  */
 Document.prototype.importNode = function(externalNode, deep) {};
@@ -72,6 +98,7 @@ Document.prototype.importNode = function(externalNode, deep) {};
  * @constructor
  * @implements {IObject<(string|number),T>}
  * @implements {IArrayLike<T>}
+ * @implements {Iterable<T>}
  * @template T
  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-75708506
  */
@@ -101,26 +128,44 @@ HTMLCollection.prototype.namedItem = function(name) {};
 
 /**
  * @constructor
- * @implements {IObject<(string|number),HTMLOptionElement>}
- * @implements {IArrayLike<!HTMLOptionElement>}
- * @see http://www.w3.org/TR/DOM-Level-2-HTML/html.html#HTMLOptionsCollection
+ * @extends {HTMLCollection<HTMLOptionElement>}
+ * @see https://html.spec.whatwg.org/multipage/common-dom-interfaces.html#htmloptionscollection
  */
 function HTMLOptionsCollection() {}
 
 /**
  * @type {number}
- * @see http://www.w3.org/TR/DOM-Level-2-HTML/html.html#HTMLOptionsCollection-length
+ * @see https://html.spec.whatwg.org/multipage/common-dom-interfaces.html#dom-htmloptionscollection-length
+ * @nosideeffects
  */
 HTMLOptionsCollection.prototype.length;
 
 /**
+ * @param {HTMLOptionElement|HTMLOptGroupElement} element
+ * @param {HTMLElement|number=} before
+ * @return {undefined}
+ * @see https://html.spec.whatwg.org/multipage/common-dom-interfaces.html#dom-htmloptionscollection-add
+ */
+HTMLOptionsCollection.prototype.add = function(element, before) {};
+
+/**
+ * NOTE(tjgq): The HTMLOptionsCollection#item method is inherited from
+ * HTMLCollection, but it must be declared explicitly to work around an error
+ * when building a jsinterop library for GWT.
  * @param {number} index
- * @return {Node}
- * @see http://www.w3.org/TR/DOM-Level-2-HTML/html.html#HTMLOptionsCollection-item
+ * @return {HTMLOptionElement}
+ * @override
  * @nosideeffects
  */
 HTMLOptionsCollection.prototype.item = function(index) {};
 
+/**
+ * @param {number} index
+ * @return {undefined}
+ * @see https://html.spec.whatwg.org/multipage/common-dom-interfaces.html#dom-htmloptionscollection-remove
+ */
+HTMLOptionsCollection.prototype.remove = function(index) {};
+
 /**
  * @constructor
  * @extends {Document}
@@ -210,24 +255,24 @@ HTMLDocument.prototype.open = function(opt_mimeType, opt_replace) {};
  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-98948567
  * @override
  */
-HTMLDocument.prototype.close = function() {};
-
-/**
- * @param {string} text
- * @return {undefined}
- * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-75233634
- * @override
- */
-HTMLDocument.prototype.write = function(text) {};
-
-/**
- * @param {string} text
- * @return {undefined}
- * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-35318390
- * @override
- */
-HTMLDocument.prototype.writeln = function(text) {};
-
+ HTMLDocument.prototype.close = function() {};
+
+ /**
+  * @param {string} text
+  * @return {undefined}
+  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-75233634
+  * @override
+  */
+ HTMLDocument.prototype.write = function(text) {};
+ 
+ /**
+  * @param {string} text
+  * @return {undefined}
+  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-35318390
+  * @override
+  */
+ HTMLDocument.prototype.writeln = function(text) {};
+ 
 /**
  * @param {string} elementName
  * @return {!NodeList<!Element>}
@@ -245,7 +290,7 @@ HTMLDocument.prototype.getElementsByName = function(elementName) {};
  * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/traversal.html#Traversal-Document
  * @nosideeffects
  */
-HTMLDocument.prototype.createNodeIterator = function(
+ HTMLDocument.prototype.createNodeIterator = function(
     root, whatToShow, filter, entityReferenceExpansion) {};
 
 /**
@@ -268,7 +313,7 @@ HTMLDocument.prototype.createTreeWalker = function(
 var TraversalDocument;
 
 /**
- * @interface
+ * @record
  * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/traversal.html#Traversal-NodeFilter
 */
 function NodeFilter() {}
@@ -405,13 +450,6 @@ TreeWalker.prototype.currentNode;
  */
 function HTMLElement() {}
 
-/**
- * @implicitCast
- * @type {string}
- * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-63534901
- */
-HTMLElement.prototype.id;
-
 /**
  * @type {string}
  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-78276800
@@ -497,6 +535,7 @@ HTMLLinkElement.prototype.charset;
 
 /**
  * @type {string}
+ * @implicitCast
  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-33532588
  */
 HTMLLinkElement.prototype.href;
@@ -540,6 +579,12 @@ HTMLLinkElement.prototype.type;
 /** @type {StyleSheet} */
 HTMLLinkElement.prototype.sheet;
 
+/**
+ * @type {!DOMTokenList}
+ * @see https://github.com/WICG/webpackage/blob/master/explainers/subresource-loading.md
+ */
+HTMLLinkElement.prototype.resources;
+
 /**
  * @constructor
  * @extends {HTMLElement}
@@ -593,6 +638,7 @@ function HTMLBaseElement() {}
 
 /**
  * @type {string}
+ * @implicitCast
  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-65382887
  */
 HTMLBaseElement.prototype.href;
@@ -710,7 +756,6 @@ function HTMLFormControlsCollection() {}
  * @see https://html.spec.whatwg.org/multipage/infrastructure.html#dom-htmlformcontrolscollection-nameditem
  * @nosideeffects
  * @override
- * @suppress {newCheckTypes}
  */
 HTMLFormControlsCollection.prototype.namedItem = function(name) {};
 
@@ -722,7 +767,7 @@ HTMLFormControlsCollection.prototype.namedItem = function(name) {};
 function HTMLFormElement() {}
 
 /**
- * @type {HTMLFormControlsCollection<!HTMLElement>}
+ * @type {!HTMLFormControlsCollection<!HTMLElement>}
  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-76728479
  */
 HTMLFormElement.prototype.elements;
@@ -747,6 +792,7 @@ HTMLFormElement.prototype.acceptCharset;
 
 /**
  * @type {string}
+ * @implicitCast
  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-74049184
  */
 HTMLFormElement.prototype.action;
@@ -954,6 +1000,20 @@ HTMLOptionElement.prototype.text;
  */
 HTMLOptionElement.prototype.value;
 
+
+
+/**
+ * @constructor
+ * @extends {HTMLOptionElement}
+ * @param {*=} opt_text
+ * @param {*=} opt_value
+ * @param {*=} opt_defaultSelected
+ * @param {*=} opt_selected
+ */
+function Option(opt_text, opt_value, opt_defaultSelected, opt_selected) {}
+
+
+
 /**
  * @constructor
  * @extends {HTMLElement}
@@ -1041,6 +1101,7 @@ HTMLInputElement.prototype.size;
 
 /**
  * @type {string}
+ * @implicitCast
  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-97320704
  */
 HTMLInputElement.prototype.src;
@@ -1618,6 +1679,7 @@ HTMLAnchorElement.prototype.coords;
 
 /**
  * @type {string}
+ * @implicitCast
  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-88517319
  */
 HTMLAnchorElement.prototype.href;
@@ -1803,6 +1865,7 @@ HTMLObjectElement.prototype.code;
 
 /**
  * @type {string}
+ * @implicitCast
  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-25709136
  */
 HTMLObjectElement.prototype.codeBase;
@@ -1821,6 +1884,7 @@ HTMLObjectElement.prototype.contentDocument;
 
 /**
  * @type {string}
+ * @implicitCast
  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-81766986
  */
 HTMLObjectElement.prototype.data;
@@ -2045,6 +2109,7 @@ HTMLAreaElement.prototype.coords;
 
 /**
  * @type {string}
+ * @implicitCast
  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-34672936
  */
 HTMLAreaElement.prototype.href;
@@ -2104,14 +2169,21 @@ HTMLScriptElement.prototype.event;
  */
 HTMLScriptElement.prototype.htmlFor;
 
+/**
+ * @type {?function(!Event)}
+ */
+HTMLScriptElement.prototype.onreadystatechange;
+
 /**
  * @type {string}
+ * @implicitCast
  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-75147231
  */
 HTMLScriptElement.prototype.src;
 
 /**
  * @type {string}
+ * @implicitCast
  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-46872999
  */
 HTMLScriptElement.prototype.text;
@@ -2436,7 +2508,7 @@ HTMLTableRowElement.prototype.deleteCell = function(index) {};
 
 /**
  * @param {number} index
- * @return {HTMLElement}
+ * @return {!HTMLElement}
  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-68927016
  */
 HTMLTableRowElement.prototype.insertCell = function(index) {};
@@ -2616,6 +2688,7 @@ HTMLFrameElement.prototype.scrolling;
 
 /**
  * @type {string}
+ * @implicitCast
  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-78799535
  */
 HTMLFrameElement.prototype.src;
@@ -2684,6 +2757,7 @@ HTMLIFrameElement.prototype.scrolling;
 
 /**
  * @type {string}
+ * @implicitCast
  * @see http://www.w3.org/TR/2000/CR-DOM-Level-2-20000510/html.html#ID-43933957
  */
 HTMLIFrameElement.prototype.src;
@@ -2696,31 +2770,253 @@ HTMLIFrameElement.prototype.src;
 HTMLIFrameElement.prototype.width;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Core/core.html#ID-258A00AF
  */
-DOMException.INVALID_STATE_ERR = 11;
+DOMException.INVALID_STATE_ERR;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Core/core.html#ID-258A00AF
  */
-DOMException.SYNTAX_ERR = 12;
+DOMException.SYNTAX_ERR;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Core/core.html#ID-258A00AF
  */
-DOMException.INVALID_MODIFICATION_ERR = 13;
+DOMException.INVALID_MODIFICATION_ERR;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Core/core.html#ID-258A00AF
  */
-DOMException.NAMESPACE_ERR = 14;
+DOMException.NAMESPACE_ERR;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Core/core.html#ID-258A00AF
  */
-DOMException.INVALID_ACCESS_ERR = 15;
+DOMException.INVALID_ACCESS_ERR;
+/**
+ * @type {boolean}
+ * @see https://developer.mozilla.org/en/DOM/window.closed
+ */
+Window.prototype.closed;
+
+/**
+ * @type {HTMLObjectElement|HTMLIFrameElement|null}
+ * @see https://developer.mozilla.org/en/DOM/window.frameElement
+ */
+Window.prototype.frameElement;
+
+/**
+ * Allows lookup of frames by index or by name.
+ * @type {!Window}
+ * @see https://developer.mozilla.org/en/DOM/window.frames
+ */
+Window.prototype.frames;
+
+/**
+ * @type {!History}
+ * @suppress {duplicate}
+ * @see https://developer.mozilla.org/en/DOM/window.history
+ */
+var history;
+
+/**
+ * @type {!History}
+ * @see https://developer.mozilla.org/en/DOM/window.history
+ */
+Window.prototype.history;
+
+/**
+ * Returns the number of frames (either frame or iframe elements) in the
+ * window.
+ *
+ * @type {number}
+ * @see https://developer.mozilla.org/en/DOM/window.length
+ */
+Window.prototype.length;
+
+/**
+ * Location has an exception in the DeclaredGlobalExternsOnWindow pass
+ * so we have to manually include it:
+ * https://github.com/google/closure-compiler/blob/master/src/com/google/javascript/jscomp/DeclaredGlobalExternsOnWindow.java#L116
+ *
+ * @type {!Location}
+ * @implicitCast
+ * @see https://developer.mozilla.org/en/DOM/window.location
+ */
+Window.prototype.location;
+
+/**
+
+ * @type {string}
+ * @see https://developer.mozilla.org/en/DOM/window.name
+ */
+Window.prototype.name;
+
+/**
+ * @type {!Navigator}
+ * @see https://developer.mozilla.org/en/DOM/window.navigator
+ */
+Window.prototype.navigator;
+
+/**
+ * @type {?Window}
+ * @see https://developer.mozilla.org/en/DOM/window.opener
+ */
+Window.prototype.opener;
+
+/**
+ * @type {!Window}
+ * @see https://developer.mozilla.org/en/DOM/window.parent
+ */
+Window.prototype.parent;
+
+/**
+ * @type {!Window}
+ * @see https://developer.mozilla.org/en/DOM/window.self
+ */
+Window.prototype.self;
+
+/**
+ * @type {?string}
+ * @see https://developer.mozilla.org/en/DOM/window.status
+ */
+Window.prototype.status;
+
+/**
+ * @interface
+ * @see https://html.spec.whatwg.org/multipage/window-object.html#the-status-bar-barprop-object
+ */
+function BarProp() {}
+
+/** @const {boolean} */
+BarProp.prototype.visible;
+
+/**
+ * @type {!BarProp}
+ * @see https://developer.mozilla.org/en/DOM/window.locationbar
+ */
+Window.prototype.locationbar;
+
+/**
+ * @type {!BarProp}
+ * @see https://developer.mozilla.org/en/DOM/window.menubar
+ */
+Window.prototype.menubar;
+
+/**
+ * @type {!BarProp}
+ * @see https://developer.mozilla.org/en/DOM/window.personalbar
+ */
+Window.prototype.personalbar;
+
+
+/**
+ * @type {!BarProp}
+ * @see https://developer.mozilla.org/en/DOM/window.scrollbars
+ */
+Window.prototype.scrollbars;
+
+/**
+ * @type {!BarProp}
+ * @see https://developer.mozilla.org/en/DOM/window.statusbar
+ */
+Window.prototype.statusbar;
+
+/**
+ * @type {!BarProp}
+ * @see https://developer.mozilla.org/en/DOM/window.toolbar
+ */
+Window.prototype.toolbar;
+
+/**
+ * @type {!Window}
+ * @see https://developer.mozilla.org/en/DOM/window.self
+ */
+Window.prototype.top;
+
+/**
+ * @type {!Window}
+ * @see https://developer.mozilla.org/en/DOM/window.self
+ */
+Window.prototype.window;
+
+/**
+ * @param {*} message
+ * @see https://developer.mozilla.org/en/DOM/window.alert
+ * @return {undefined}
+ */
+Window.prototype.alert = function(message) {};
+
+/**
+ * @param {*} message
+ * @return {boolean}
+ * @see https://developer.mozilla.org/en/DOM/window.confirm
+ */
+Window.prototype.confirm = function(message) {};
+
+/**
+ * @param {string} message
+ * @param {string=} value
+ * @return {?string}
+ * @see https://developer.mozilla.org/en/DOM/window.prompt
+ */
+Window.prototype.prompt = function(message, value) {};
+
+/**
+ * @see https://developer.mozilla.org/en/DOM/window.blur
+ * @return {undefined}
+ */
+Window.prototype.blur = function() {};
+
+/**
+ * @see https://developer.mozilla.org/en/DOM/window.close
+ * @return {undefined}
+ */
+Window.prototype.close = function() {};
+
+/**
+ * @see https://developer.mozilla.org/en/DOM/window.focus
+ * @return {undefined}
+ */
+Window.prototype.focus = function() {};
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/Window/print
+ * @return {undefined}
+ */
+Window.prototype.print = function() {};
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/Window/stop
+ * @return {undefined}
+ */
+Window.prototype.stop = function() {};
+
+/**
+ * @param {*=} url
+ * @param {string=} windowName
+ * @param {string=} windowFeatures
+ * @param {boolean=} replace
+ * @return {Window}
+ * @see http://msdn.microsoft.com/en-us/library/ms536651(VS.85).aspx
+ */
+Window.prototype.open = function(url, windowName, windowFeatures, replace) {};
+
+/**
+ * @type {string}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/Element/innerHTML
+ * @implicitCast
+ */
+Element.prototype.innerHTML;
+
+/**
+ * @type {string}
+ * @implicitCast
+ * @see https://w3c.github.io/DOM-Parsing/#extensions-to-the-element-interface
+ */
+Element.prototype.outerHTML;
diff --git a/javascript/externs/web/w3c_dom3.js b/javascript/externs/web/w3c_dom3.js
index 6ddcaefa7030..c87a840ebedf 100644
--- a/javascript/externs/web/w3c_dom3.js
+++ b/javascript/externs/web/w3c_dom3.js
@@ -32,16 +32,16 @@
 DOMException.prototype.code;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#ID-258A00AF
  */
-DOMException.VALIDATION_ERR = 16;
+DOMException.VALIDATION_ERR;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#ID-258A00AF
  */
-DOMException.TYPE_MISMATCH_ERR = 17;
+DOMException.TYPE_MISMATCH_ERR;
 
 /**
  * @constructor
@@ -72,52 +72,6 @@ DOMStringList.prototype.contains = function(str) {};
  */
 DOMStringList.prototype.item = function(index) {};
 
-/**
- * @constructor
- * @implements {IArrayLike<string>}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#NameList
- */
-function NameList() {}
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#NameList-length
- */
-NameList.prototype.length;
-
-/**
- * @param {string} str
- * @return {boolean}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#NameList-contains
- * @nosideeffects
- */
-NameList.prototype.contains = function(str) {};
-
-/**
- * @param {?string} namespaceURI
- * @param {string} name
- * @return {boolean}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#NameList-containsNS
- * @nosideeffects
- */
-NameList.prototype.containsNS = function(namespaceURI, name) {};
-
-/**
- * @param {number} index
- * @return {string}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#NameList-getName
- * @nosideeffects
- */
-NameList.prototype.getName = function(index) {};
-
-/**
- * @param {number} index
- * @return {string}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#NameList-getNamespaceURI
- * @nosideeffects
- */
-NameList.prototype.getNamespaceURI = function(index) {};
-
 /**
  * @constructor
  * @implements {IArrayLike<!DOMImplementation>}
@@ -148,9 +102,9 @@ function DOMImplementationSource() {}
 /**
  * @param {?string} namespaceURI
  * @param {string} publicId
- * @param {DocumentType} doctype
+ * @param {DocumentType=} doctype
  * @return {Document}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Level-2-Core-DOM-createDocument
+ * @see https://dom.spec.whatwg.org/#ref-for-dom-domimplementation-createdocument%E2%91%A0
  * @nosideeffects
  */
 DOMImplementation.prototype.createDocument = function(namespaceURI, publicId, doctype) {};
@@ -181,15 +135,6 @@ DOMImplementationSource.prototype.getDOMImplementation = function(features) {};
  */
 DOMImplementationSource.prototype.getDOMImplementationList = function(features) {};
 
-/**
- * @param {string} feature
- * @param {string} version
- * @return {Object}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#DOMImplementation3-getFeature
- * @nosideeffects
- */
-DOMImplementation.prototype.getFeature = function(feature, version) {};
-
 /**
  * @param {Node} externalNode
  * @return {Node}
@@ -203,24 +148,12 @@ Document.prototype.adoptNode = function(externalNode) {};
  */
 Document.prototype.documentURI;
 
-/**
- * @type {DOMConfiguration}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Document3-domConfig
- */
-Document.prototype.domConfig;
-
 /**
  * @type {string}
  * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Document3-inputEncoding
  */
 Document.prototype.inputEncoding;
 
-/**
- * @type {boolean}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Document3-strictErrorChecking
- */
-Document.prototype.strictErrorChecking;
-
 /**
  * @type {string}
  * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Document3-encoding
@@ -239,21 +172,6 @@ Document.prototype.xmlStandalone;
  */
 Document.prototype.xmlVersion;
 
-/**
- * @return {undefined}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Document3-normalizeDocument
- */
-Document.prototype.normalizeDocument = function() {};
-
-/**
- * @param {Node} n
- * @param {?string} namespaceURI
- * @param {string} qualifiedName
- * @return {Node}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Document3-renameNode
- */
-Document.prototype.renameNode = function(n, namespaceURI, qualifiedName) {};
-
 /**
  * @type {?string}
  * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Node3-baseURI
@@ -286,40 +204,40 @@ Node.prototype.prefix;
 Node.prototype.textContent;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Node-DOCUMENT_POSITION_DISCONNECTED
  */
-Node.DOCUMENT_POSITION_DISCONNECTED = 0x01;
+Node.DOCUMENT_POSITION_DISCONNECTED;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Node-DOCUMENT_POSITION_PRECEDING
  */
-Node.DOCUMENT_POSITION_PRECEDING    = 0x02;
+Node.DOCUMENT_POSITION_PRECEDING;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Node-DOCUMENT_POSITION_FOLLOWING
  */
-Node.DOCUMENT_POSITION_FOLLOWING    = 0x04;
+Node.DOCUMENT_POSITION_FOLLOWING;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Node-DOCUMENT_POSITION_CONTAINS
  */
-Node.DOCUMENT_POSITION_CONTAINS     = 0x08;
+Node.DOCUMENT_POSITION_CONTAINS;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Node-DOCUMENT_POSITION_CONTAINED_BY
  */
-Node.DOCUMENT_POSITION_CONTAINED_BY = 0x10;
+Node.DOCUMENT_POSITION_CONTAINED_BY;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Node-DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC
  */
-Node.DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC = 0x20;
+Node.DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC;
 
 /**
  * @param {Node} other
@@ -377,15 +295,6 @@ Node.prototype.isEqualNode = function(arg) {};
  */
 Node.prototype.isSameNode = function(other) {};
 
-/**
- * @param {string} feature
- * @param {string} version
- * @return {boolean}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Level-2-Core-Node-supports
- * @nosideeffects
- */
-Node.prototype.isSupported = function(feature, version) {};
-
 /**
  * @param {string} prefix
  * @return {string}
@@ -408,15 +317,6 @@ Node.prototype.lookupPrefix = function(namespaceURI) {};
  */
 Node.prototype.normalize = function() {};
 
-/**
- * @param {Object} key
- * @param {Object} data
- * @param {UserDataHandler} handler
- * @return {Object}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Node3-setUserData'
- */
-Node.prototype.setUserData = function(key, data, handler) {};
-
 /**
  * @param {string} query
  * @return {?Element}
@@ -445,18 +345,6 @@ Attr.prototype.ownerElement;
  */
 Attr.prototype.isId;
 
-/**
- * @type {TypeInfo}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Attr-schemaTypeInfo
- */
-Attr.prototype.schemaTypeInfo;
-
-/**
- * @type {TypeInfo}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Element-schemaTypeInfo
- */
-Element.prototype.schemaTypeInfo;
-
 /**
  * @param {?string} namespaceURI
  * @param {string} localName
@@ -527,144 +415,12 @@ Element.prototype.setAttributeNodeNS = function(newAttr) {};
  */
 Element.prototype.setAttributeNS = function(namespaceURI, qualifiedName, value) {};
 
-/**
- * @param {string} name
- * @param {boolean} isId
- * @return {undefined}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#ID-ElSetIdAttr
- */
-Element.prototype.setIdAttribute = function(name, isId) {};
-
-/**
- * @param {Attr} idAttr
- * @param {boolean} isId
- * @return {undefined}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#ID-ElSetIdAttrNode
- */
-Element.prototype.setIdAttributeNode = function(idAttr, isId) {};
-
-/**
- * @param {?string} namespaceURI
- * @param {string} localName
- * @param {boolean} isId
- * @return {undefined}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#ID-ElSetIdAttrNS
- */
-Element.prototype.setIdAttributeNS = function(namespaceURI, localName, isId) {};
-
 /**
  * @type {string}
  * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Text3-wholeText
  */
 Text.prototype.wholeText;
 
-/**
- * @param {string} newText
- * @return {Text}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Text3-replaceWholeText
- */
-Text.prototype.replaceWholeText = function(newText) {};
-
-/**
- * @constructor
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#TypeInfo
- */
-function TypeInfo() {}
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#TypeInfo-DERIVATION_EXTENSION
- */
-TypeInfo.prototype.DERIVATION_EXTENSION;
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#TypeInfo-DERIVATION_LIST
- */
-TypeInfo.prototype.DERIVATION_LIST;
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#TypeInfo-DERIVATION_RESTRICTION
- */
-TypeInfo.prototype.DERIVATION_RESTRICTION;
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#TypeInfo-DERIVATION_UNION
- */
-TypeInfo.prototype.DERIVATION_UNION;
-
-/**
- * @type {string}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#TypeInfo-typeName
- */
-TypeInfo.prototype.typeName;
-
-/**
- * @type {string}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#TypeInfo-typeNamespace
- */
-TypeInfo.prototype.typeNamespace;
-
-/**
- * @param {string} typeNamespaceArg
- * @param {string} typeNameArg
- * @param {number} derivationMethod
- * @return {boolean}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#TypeInfo-isDerivedFrom
- * @nosideeffects
- */
-TypeInfo.prototype.isDerivedFrom = function(typeNamespaceArg, typeNameArg, derivationMethod) {};
-
-/**
- * @constructor
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#UserDataHandler
- */
-function UserDataHandler() {}
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#UserDataHandler-CLONED
- */
-UserDataHandler.prototype.NODE_CLONED = 1;
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#UserDataHandler-IMPORTED
- */
-UserDataHandler.prototype.NODE_IMPORTED = 2;
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#UserDataHandler-DELETED
- */
-UserDataHandler.prototype.NODE_DELETED = 3;
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#UserDataHandler-RENAMED
- */
-UserDataHandler.prototype.NODE_RENAMED = 4;
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#UserDataHandler-ADOPTED
- */
-UserDataHandler.prototype.NODE_ADOPTED = 5;
-
-/**
- * @param {number} operation
- * @param {string} key
- * @param {*=} opt_data
- * @param {?Node=} opt_src
- * @param {?Node=} opt_dst
- * @return {undefined}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#ID-handleUserDataEvent
- */
-UserDataHandler.prototype.handle = function(operation, key, opt_data,
-  opt_src, opt_dst) {};
-
 /**
  * @constructor
  * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#ERROR-Interfaces-DOMError
@@ -696,22 +452,22 @@ DOMError.prototype.relatedData;
 DOMError.prototype.relatedException;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#ERROR-DOMError-severity-warning
  */
-DOMError.SEVERITY_WARNING = 1;
+DOMError.SEVERITY_WARNING;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#ERROR-DOMError-severity-error
  */
-DOMError.SEVERITY_ERROR = 2;
+DOMError.SEVERITY_ERROR;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#ERROR-DOMError-severity-fatal-error
  */
-DOMError.SEVERITY_FATAL_ERROR = 3;
+DOMError.SEVERITY_FATAL_ERROR;
 
 /**
  * @type {number}
@@ -786,48 +542,6 @@ DOMLocator.prototype.uri;
  */
 DOMLocator.prototype.utf16Offset;
 
-/**
- * @constructor
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#DOMConfiguration
- */
-function DOMConfiguration() {}
-
-/**
- * @type {DOMStringList}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#DOMConfiguration-parameterNames
- */
-DOMConfiguration.prototype.parameterNames;
-
-/**
- * @param {string} name
- * @return {boolean}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#DOMConfiguration-canSetParameter
- * @nosideeffects
- */
-DOMConfiguration.prototype.canSetParameter = function(name) {};
-
-/**
- * @param {string} name
- * @return {*}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#DOMConfiguration-getParameter
- * @nosideeffects
- */
-DOMConfiguration.prototype.getParameter = function(name) {};
-
-/**
- * @param {string} name
- * @param {*} value
- * @return {*}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#DOMConfiguration-property
- */
-DOMConfiguration.prototype.setParameter = function(name, value) {};
-
-/**
- * @type {string}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#ID-Core-DocType-internalSubset
- */
-DocumentType.prototype.internalSubset;
-
 /**
  * @type {string}
  * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#ID-Core-DocType-publicId
@@ -839,21 +553,3 @@ DocumentType.prototype.publicId;
  * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#ID-Core-DocType-systemId
  */
 DocumentType.prototype.systemId;
-
-/**
- * @type {string}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Entity3-inputEncoding
- */
-Entity.prototype.inputEncoding;
-
-/**
- * @type {string}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Entity3-encoding
- */
-Entity.prototype.xmlEncoding;
-
-/**
- * @type {string}
- * @see http://www.w3.org/TR/DOM-Level-3-Core/core.html#Entity3-version
- */
-Entity.prototype.xmlVersion;
diff --git a/javascript/externs/web/w3c_dom4.js b/javascript/externs/web/w3c_dom4.js
index 000ce709c1e2..d0bd05a534f1 100644
--- a/javascript/externs/web/w3c_dom4.js
+++ b/javascript/externs/web/w3c_dom4.js
@@ -46,3 +46,223 @@ Element.prototype.remove = function() {};
  * @see https://www.w3.org/TR/domcore/#dom-childnode-remove
  */
 CharacterData.prototype.remove = function() {};
+
+/**
+ * @param {...(!Node|string)} nodes
+ * @return {undefined}
+ * @see https://dom.spec.whatwg.org/#dom-childnode-replacewith
+ */
+DocumentType.prototype.replaceWith = function(nodes) {};
+
+/**
+ * @const {string}
+ * @see https://www.w3.org/TR/2015/REC-dom-20151119/#sec-domerror
+ */
+DOMException.prototype.name;
+
+/**
+ * @const {string}
+ * @see https://www.w3.org/TR/2015/REC-dom-20151119/#sec-domerror
+ */
+DOMException.prototype.message;
+
+/**
+ * @const {number}
+ * @see https://www.w3.org/TR/2015/REC-dom-20151119/#dfn-error-names-table
+ */
+DOMException.SECURITY_ERR;
+
+/**
+ * @const {number}
+ * @see https://www.w3.org/TR/2015/REC-dom-20151119/#dfn-error-names-table
+ */
+DOMException.NETWORK_ERR;
+
+/**
+ * @const {number}
+ * @see https://www.w3.org/TR/2015/REC-dom-20151119/#dfn-error-names-table
+ */
+DOMException.ABORT_ERR;
+
+/**
+ * @const {number}
+ * @see https://www.w3.org/TR/2015/REC-dom-20151119/#dfn-error-names-table
+ */
+DOMException.URL_MISMATCH_ERR;
+
+/**
+ * @const {number}
+ * @see https://www.w3.org/TR/2015/REC-dom-20151119/#dfn-error-names-table
+ */
+DOMException.QUOTA_EXCEEDED_ERR;
+
+/**
+ * @const {number}
+ * @see https://www.w3.org/TR/2015/REC-dom-20151119/#dfn-error-names-table
+ */
+DOMException.TIMEOUT_ERR;
+
+/**
+ * @const {number}
+ * @see https://www.w3.org/TR/2015/REC-dom-20151119/#dfn-error-names-table
+ */
+DOMException.INVALID_NODE_TYPE_ERR;
+
+/**
+ * @const {number}
+ * @see https://www.w3.org/TR/2015/REC-dom-20151119/#dfn-error-names-table
+ */
+DOMException.DATA_CLONE_ERR;
+
+/**
+ * @param {...(!Node|string)} nodes
+ * @return {undefined}
+ * @see https://dom.spec.whatwg.org/#dom-childnode-replacewith
+ */
+Element.prototype.replaceWith = function(nodes) {};
+
+/**
+ * @param {...(!Node|string)} nodes
+ * @return {undefined}
+ * @see https://dom.spec.whatwg.org/#dom-childnode-replacewith
+ */
+CharacterData.prototype.replaceWith = function(nodes) {};
+
+/**
+ * @return {!Array<string>}
+ * @see https://dom.spec.whatwg.org/#dom-element-getattributenames
+ */
+Element.prototype.getAttributeNames = function() {};
+
+/**
+ * @param {...(!Node|string)} nodes
+ * @return {undefined}
+ * @see https://dom.spec.whatwg.org/#dom-parentnode-append
+ */
+Element.prototype.append = function(nodes) {};
+
+/**
+ * @param {...(!Node|string)} nodes
+ * @return {undefined}
+ * @see https://dom.spec.whatwg.org/#dom-parentnode-append
+ */
+Document.prototype.append = function(nodes) {};
+
+/**
+ * @param {...(!Node|string)} nodes
+ * @return {undefined}
+ * @see https://dom.spec.whatwg.org/#dom-parentnode-append
+ */
+DocumentFragment.prototype.append = function(nodes) {};
+
+/**
+ * @param {...(!Node|string)} nodes
+ * @return {undefined}
+ * @see https://dom.spec.whatwg.org/#dom-parentnode-prepend
+ */
+Element.prototype.prepend = function(nodes) {};
+
+/**
+ * @param {...(!Node|string)} nodes
+ * @return {undefined}
+ * @see https://dom.spec.whatwg.org/#dom-parentnode-prepend
+ */
+Document.prototype.prepend = function(nodes) {};
+
+/**
+ * @param {...(!Node|string)} nodes
+ * @return {undefined}
+ * @see https://dom.spec.whatwg.org/#dom-parentnode-prepend
+ */
+DocumentFragment.prototype.prepend = function(nodes) {};
+
+/**
+ * @param {...(!Node|string)} nodes
+ * @return {undefined}
+ * @see https://dom.spec.whatwg.org/#dom-childnode-before
+ */
+Element.prototype.before = function(nodes) {};
+
+/**
+ * @param {...(!Node|string)} nodes
+ * @return {undefined}
+ * @see https://dom.spec.whatwg.org/#dom-childnode-before
+ */
+DocumentType.prototype.before = function(nodes) {};
+
+/**
+ * @param {...(!Node|string)} nodes
+ * @return {undefined}
+ * @see https://dom.spec.whatwg.org/#dom-childnode-before
+ */
+CharacterData.prototype.before = function(nodes) {};
+
+/**
+ * @param {...(!Node|string)} nodes
+ * @return {undefined}
+ * @see https://dom.spec.whatwg.org/#dom-childnode-after
+ */
+Element.prototype.after = function(nodes) {};
+
+/**
+ * @param {...(!Node|string)} nodes
+ * @return {undefined}
+ * @see https://dom.spec.whatwg.org/#dom-childnode-after
+ */
+DocumentType.prototype.after = function(nodes) {};
+
+/**
+ * @param {...(!Node|string)} nodes
+ * @return {undefined}
+ * @see https://dom.spec.whatwg.org/#dom-childnode-after
+ */
+CharacterData.prototype.after = function(nodes) {};
+
+/**
+ * @param {string} name
+ * @param {boolean=} force
+ * @return {boolean}
+ * @throws {DOMException}
+ * @see https://dom.spec.whatwg.org/#dom-element-toggleattribute
+ */
+Element.prototype.toggleAttribute = function(name, force) {};
+
+/**
+ * @type {Element}
+ * @see http://msdn.microsoft.com/en-us/library/ms534327(VS.85).aspx
+ */
+Node.prototype.parentElement;
+
+/**
+ * @param {string} name
+ * @return {!HTMLCollection<!Element>}
+ * @nosideeffects
+ * @see https://dom.spec.whatwg.org/#dom-document-getelementsbyclassname-classnames-classnames
+ */
+Document.prototype.getElementsByClassName = function(name) {};
+
+/**
+ * @param {string} classNames
+ * @return {!HTMLCollection<!Element>}
+ * @nosideeffects
+ * @see https://dom.spec.whatwg.org/#dom-element-getelementsbyclassname-classnames-classnames
+ */
+Element.prototype.getElementsByClassName = function(classNames) {};
+
+/**
+ * @param {string} where
+ * @param {Element} element
+ * @return {!Element}
+ * @throws {DOMException}
+ * @see https://dom.spec.whatwg.org/#dom-element-insertadjacentelement
+ */
+Element.prototype.insertAdjacentElement = function(where, element) {};
+
+/**
+ * @param {string} where
+ * @param {string} data
+ * @return {undefined}
+ * @throws {DOMException}
+ * @see https://dom.spec.whatwg.org/#dom-element-insertadjacenttext
+ */
+Element.prototype.insertAdjacentText = function(where, data) {};
diff --git a/javascript/externs/web/w3c_event.js b/javascript/externs/web/w3c_event.js
index 8b66d6a4d809..bbe0ba06624f 100644
--- a/javascript/externs/web/w3c_event.js
+++ b/javascript/externs/web/w3c_event.js
@@ -26,33 +26,38 @@
 
 /**
  * @interface
+ * @see https://dom.spec.whatwg.org/#interface-eventtarget
  */
 function EventTarget() {}
 
 /**
- * TODO(tbreisacher): Change the type of useCapture to be
- * {boolean|!EventListenerOptions}, here and in removeEventListener.
- *
  * @param {string} type
- * @param {EventListener|function(!Event):(boolean|undefined)} listener
- * @param {boolean} useCapture
+ * @param {EventListener|function(this:THIS, !Event):*} listener
+ * @param {(boolean|!AddEventListenerOptions)=} opt_options
  * @return {undefined}
+ * @this {THIS}
+ * @template THIS
+ * @see https://dom.spec.whatwg.org/#dom-eventtarget-addeventlistener
  */
-EventTarget.prototype.addEventListener = function(type, listener, useCapture)
-    {};
+EventTarget.prototype.addEventListener = function(type, listener, opt_options) {
+};
 
 /**
  * @param {string} type
- * @param {EventListener|function(!Event):(boolean|undefined)} listener
- * @param {boolean} useCapture
+ * @param {EventListener|function(this:THIS, !Event):*} listener
+ * @param {(boolean|!EventListenerOptions)=} opt_options
  * @return {undefined}
+ * @this {THIS}
+ * @template THIS
+ * @see https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener
  */
-EventTarget.prototype.removeEventListener = function(type, listener, useCapture)
-    {};
+EventTarget.prototype.removeEventListener = function(
+    type, listener, opt_options) {};
 
 /**
  * @param {!Event} evt
  * @return {boolean}
+ * @see https://dom.spec.whatwg.org/#dom-eventtarget-dispatchevent
  */
 EventTarget.prototype.dispatchEvent = function(evt) {};
 
@@ -99,23 +104,22 @@ EventInit.prototype.composed;
 function Event(type, opt_eventInitDict) {}
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Events/ecma-script-binding.html
  */
-Event.AT_TARGET;
+Event.CAPTURING_PHASE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Events/ecma-script-binding.html
  */
-Event.BUBBLING_PHASE;
+Event.AT_TARGET;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-2-Events/ecma-script-binding.html
  */
-Event.CAPTURING_PHASE;
-
+Event.BUBBLING_PHASE;
 
 /** @type {string} */
 Event.prototype.type;
@@ -163,8 +167,8 @@ Event.prototype.preventDefault = function() {};
 
 /**
  * @param {string} eventTypeArg
- * @param {boolean} canBubbleArg
- * @param {boolean} cancelableArg
+ * @param {boolean=} canBubbleArg
+ * @param {boolean=} cancelableArg
  * @return {undefined}
  */
 Event.prototype.initEvent = function(eventTypeArg, canBubbleArg, cancelableArg) {};
@@ -172,18 +176,20 @@ Event.prototype.initEvent = function(eventTypeArg, canBubbleArg, cancelableArg)
 /**
  * @record
  * @extends {EventInit}
+ * @template T
  * @see https://dom.spec.whatwg.org/#dictdef-customeventinit
  */
 function CustomEventInit() {}
 
-/** @type {(*|undefined)} */
+/** @type {(T|undefined)} */
 CustomEventInit.prototype.detail;
 
 /**
  * @constructor
  * @extends {Event}
  * @param {string} type
- * @param {CustomEventInit=} opt_eventInitDict
+ * @param {CustomEventInit<T>=} opt_eventInitDict
+ * @template T
  * @see http://www.w3.org/TR/DOM-Level-3-Events/#interface-CustomEvent
  */
 function CustomEvent(type, opt_eventInitDict) {}
@@ -192,14 +198,14 @@ function CustomEvent(type, opt_eventInitDict) {}
  * @param {string} eventType
  * @param {boolean} bubbles
  * @param {boolean} cancelable
- * @param {*} detail
+ * @param {T} detail
  * @return {undefined}
  */
 CustomEvent.prototype.initCustomEvent = function(
     eventType, bubbles, cancelable, detail) {};
 
 /**
- * @type {*}
+ * @type {T}
  */
 CustomEvent.prototype.detail;
 
@@ -430,6 +436,7 @@ KeyboardEventInit.prototype.char;
 KeyboardEventInit.prototype.locale;
 
 /**
+ * @see https://w3c.github.io/uievents/#idl-keyboardevent
  * @constructor
  * @extends {UIEvent}
  * @param {string} type
@@ -452,6 +459,18 @@ KeyboardEvent.prototype.altKey;
 /** @type {boolean} */
 KeyboardEvent.prototype.metaKey;
 
+/** @type {number} */
+KeyboardEvent.DOM_KEY_LOCATION_STANDARD;
+
+/** @type {number} */
+KeyboardEvent.DOM_KEY_LOCATION_LEFT;
+
+/** @type {number} */
+KeyboardEvent.DOM_KEY_LOCATION_RIGHT;
+
+/** @type {number} */
+KeyboardEvent.DOM_KEY_LOCATION_NUMPAD;
+
 /**
  * @param {string} keyIdentifierArg
  * @return {boolean}
@@ -552,3 +571,33 @@ InputEvent.prototype.inputType;
 
 /** @type {?DataTransfer} */
 InputEvent.prototype.dataTransfer;
+
+
+/**
+ * @record
+ * @extends {EventInit}
+ * @see https://html.spec.whatwg.org/multipage/webappapis.html#promiserejectioneventinit
+ */
+function PromiseRejectionEventInit() {}
+
+/** @type {undefined|!Promise<*>} */
+PromiseRejectionEventInit.prototype.promise;
+
+/** @type {*} */
+PromiseRejectionEventInit.prototype.reason;
+
+
+/**
+ * @constructor
+ * @extends {Event}
+ * @param {string} type
+ * @param {PromiseRejectionEventInit=} eventInitDict
+ * @see https://html.spec.whatwg.org/multipage/webappapis.html#promiserejectionevent
+ */
+function PromiseRejectionEvent(type, eventInitDict) {}
+
+/** @type {!Promise<*>} */
+PromiseRejectionEvent.prototype.promise;
+
+/** @type {*} */
+PromiseRejectionEvent.prototype.reason;
\ No newline at end of file
diff --git a/javascript/externs/web/w3c_geolocation.js b/javascript/externs/web/w3c_geolocation.js
index afe2b52238aa..be541faac1cf 100644
--- a/javascript/externs/web/w3c_geolocation.js
+++ b/javascript/externs/web/w3c_geolocation.js
@@ -27,8 +27,18 @@
 function Geolocation() {}
 
 /**
- * @param {function(!GeolocationPosition)} successCallback
- * @param {(function(!GeolocationPositionError)|null)=} opt_errorCallback
+ * @typedef {function(!GeolocationPosition): void}
+ */
+var PositionCallback;
+
+/**
+ * @typedef {function(!GeolocationPositionError): void}
+ */
+var PositionErrorCallback;
+
+/**
+ * @param {PositionCallback} successCallback
+ * @param {PositionErrorCallback=} opt_errorCallback
  * @param {GeolocationPositionOptions=} opt_options
  * @return {undefined}
  */
@@ -37,8 +47,8 @@ Geolocation.prototype.getCurrentPosition = function(successCallback,
                                                        opt_options) {};
 
 /**
- * @param {function(!GeolocationPosition)} successCallback
- * @param {(function(!GeolocationPositionError)|null)=} opt_errorCallback
+ * @param {PositionCallback} successCallback
+ * @param {PositionErrorCallback=} opt_errorCallback
  * @param {GeolocationPositionOptions=} opt_options
  * @return {number}
  */
@@ -54,7 +64,7 @@ Geolocation.prototype.clearWatch = function(watchId) {};
 
 
 /**
- * @constructor
+ * @record
  * @see http://www.w3.org/TR/geolocation-API/#coordinates
  */
 function GeolocationCoordinates() {}
@@ -64,24 +74,24 @@ GeolocationCoordinates.prototype.latitude;
 GeolocationCoordinates.prototype.longitude;
 /** @type {number} */
 GeolocationCoordinates.prototype.accuracy;
-/** @type {number} */
+/** @type {number|null} */
 GeolocationCoordinates.prototype.altitude;
-/** @type {number} */
+/** @type {number|null} */
 GeolocationCoordinates.prototype.altitudeAccuracy;
-/** @type {number} */
+/** @type {number|null} */
 GeolocationCoordinates.prototype.heading;
-/** @type {number} */
+/** @type {number|null} */
 GeolocationCoordinates.prototype.speed;
 
 
 /**
- * @constructor
+ * @record
  * @see http://www.w3.org/TR/geolocation-API/#position
  */
 function GeolocationPosition() {}
 /** @type {GeolocationCoordinates} */
 GeolocationPosition.prototype.coords;
-/** @type {Date} */
+/** @type {number} */
 GeolocationPosition.prototype.timestamp;
 
 
@@ -99,7 +109,7 @@ GeolocationPositionOptions.prototype.timeout;
 
 
 /**
- * @constructor
+ * @record
  * @see http://www.w3.org/TR/geolocation-API/#position-error
  */
 function GeolocationPositionError() {}
@@ -107,13 +117,13 @@ function GeolocationPositionError() {}
 GeolocationPositionError.prototype.code;
 /** @type {string} */
 GeolocationPositionError.prototype.message;
-/** @type {number} */
+/** @const {number} */
 GeolocationPositionError.prototype.UNKNOWN_ERROR;
-/** @type {number} */
+/** @const {number} */
 GeolocationPositionError.prototype.PERMISSION_DENIED;
-/** @type {number} */
+/** @const {number} */
 GeolocationPositionError.prototype.POSITION_UNAVAILABLE;
-/** @type {number} */
+/** @const {number} */
 GeolocationPositionError.prototype.TIMEOUT;
 
 /** @type {Geolocation} */
diff --git a/javascript/externs/web/w3c_indexeddb.js b/javascript/externs/web/w3c_indexeddb.js
index d0a87381c244..7d89363afac0 100644
--- a/javascript/externs/web/w3c_indexeddb.js
+++ b/javascript/externs/web/w3c_indexeddb.js
@@ -15,281 +15,140 @@
  */
 
 /**
- * @fileoverview Definitions for W3C's IndexedDB API. In Chrome all the
- * IndexedDB classes are prefixed with 'webkit'. In order to access constants
- * and static methods of these classes they must be duplicated with the
- * prefix here.
- * @see http://www.w3.org/TR/IndexedDB/
+ * @fileoverview Definitions for W3C's IndexedDB API and IndexedDB API 2.0.
+ * @see http://www.w3.org/TR/2015/REC-IndexedDB-20150108/
+ * @see https://www.w3.org/TR/2017/WD-IndexedDB-2-20170313/
  *
  * @externs
  * @author guido.tapia@picnet.com.au (Guido Tapia)
+ * @author vobruba.martin@gmail.com (Martin Vobruba)
  */
 
-/** @type {!IDBFactory|undefined} */
-Window.prototype.moz_indexedDB;
+/** @type {!IDBFactory} */
+var indexedDB;
 
 /** @type {!IDBFactory|undefined} */
-Window.prototype.mozIndexedDB;
+ServiceWorkerGlobalScope.prototype.indexedDB;
 
-/** @type {!IDBFactory|undefined} */
-Window.prototype.webkitIndexedDB;
 
-/** @type {!IDBFactory|undefined} */
-Window.prototype.msIndexedDB;
-
-/** @type {!IDBFactory|undefined} */
-Window.prototype.indexedDB;
 
 /**
- * @constructor
- * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBFactory
- */
-function IDBFactory() {}
-
-/**
- * @param {string} name The name of the database to open.
- * @param {number=} opt_version The version at which to open the database.
- * @return {!IDBOpenDBRequest} The IDBRequest object.
- */
-IDBFactory.prototype.open = function(name, opt_version) {};
-
-/**
- * @param {string} name The name of the database to delete.
- * @return {!IDBOpenDBRequest} The IDBRequest object.
- */
-IDBFactory.prototype.deleteDatabase = function(name) {};
-
-/**
- * @constructor
- * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBDatabaseException
- */
-function IDBDatabaseException() {}
-
-/**
- * @constructor
- * @extends {IDBDatabaseException}
- * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBDatabaseException
- */
-function webkitIDBDatabaseException() {}
-
-/**
- * @const
- * @type {number}
- */
-IDBDatabaseException.UNKNOWN_ERR;
-
-/**
- * @const
- * @type {number}
+ * Possible values: 'readonly', 'readwrite', 'versionchange'
+ *
+ * @typedef {string}
+ * @see https://www.w3.org/TR/IndexedDB/#idl-def-IDBTransactionMode
  */
-webkitIDBDatabaseException.UNKNOWN_ERR;
+var IDBTransactionMode;
 
-/**
- * @const
- * @type {number}
- */
-IDBDatabaseException.NON_TRANSIENT_ERR;
 
 /**
- * @const
- * @type {number}
- */
-webkitIDBDatabaseException.NON_TRANSIENT_ERR;
-
-/**
- * @const
- * @type {number}
+ * Possible values: 'pending', 'done'
+ *
+ * @typedef {string}
+ * @see https://www.w3.org/TR/IndexedDB/#idl-def-IDBRequestReadyState
  */
-IDBDatabaseException.NOT_FOUND_ERR;
+var IDBRequestReadyState;
 
-/**
- * @const
- * @type {number}
- */
-webkitIDBDatabaseException.NOT_FOUND_ERR;
 
 /**
- * @const
- * @type {number}
+ * Possible values: 'next', 'nextunique', 'prev', 'prevunique'
+ *
+ * @typedef {string}
+ * @see https://www.w3.org/TR/IndexedDB/#idl-def-IDBCursorDirection
  */
-IDBDatabaseException.CONSTRAINT_ERR;
+var IDBCursorDirection;
 
-/**
- * @const
- * @type {number}
- */
-webkitIDBDatabaseException.CONSTRAINT_ERR;
 
 /**
- * @const
- * @type {number}
+ * @record
+ * @see https://www.w3.org/TR/IndexedDB/#idl-def-IDBIndexParameters
  */
-IDBDatabaseException.DATA_ERR;
+function IDBIndexParameters(){};
 
-/**
- * @const
- * @type {number}
- */
-webkitIDBDatabaseException.DATA_ERR;
+/** @type {(undefined|boolean)} */
+IDBIndexParameters.prototype.unique;
 
-/**
- * @const
- * @type {number}
- */
-IDBDatabaseException.NOT_ALLOWED_ERR;
+/** @type {(undefined|boolean)} */
+IDBIndexParameters.prototype.multiEntry;
 
-/**
- * @const
- * @type {number}
- */
-webkitIDBDatabaseException.NOT_ALLOWED_ERR;
 
 /**
- * @const
- * @type {number}
+ * @record
+ * @extends {EventInit}
+ * @see https://www.w3.org/TR/IndexedDB/#idl-def-IDBVersionChangeEventInit
  */
-IDBDatabaseException.TRANSACTION_INACTIVE_ERR;
+function IDBVersionChangeEventInit(){};
 
-/**
- * @const
- * @type {number}
- */
-webkitIDBDatabaseException.TRANSACTION_INACTIVE_ERR;
+/** @type {(undefined|number)} */
+IDBVersionChangeEventInit.prototype.oldVersion;
 
-/**
- * @const
- * @type {number}
- */
-IDBDatabaseException.ABORT_ERR;
+/** @type {(undefined|number|null)} */
+IDBVersionChangeEventInit.prototype.newVersion;
 
-/**
- * @const
- * @type {number}
- */
-webkitIDBDatabaseException.ABORT_ERR;
 
-/**
- * @const
- * @type {number}
- */
-IDBDatabaseException.READ_ONLY_ERR;
 
 /**
- * @const
- * @type {number}
+ * @record
+ * @see https://www.w3.org/TR/IndexedDB/#idl-def-IDBObjectStoreParameters
  */
-webkitIDBDatabaseException.READ_ONLY_ERR;
+function IDBObjectStoreParameters() {};
 
-/**
- * @const
- * @type {number}
- */
-IDBDatabaseException.TIMEOUT_ERR;
+/** @type {(undefined|string|!Array<string>|null)} */
+IDBObjectStoreParameters.prototype.keyPath;
 
-/**
- * @const
- * @type {number}
- */
-webkitIDBDatabaseException.TIMEOUT_ERR;
+/** @type {(undefined|boolean)} */
+IDBObjectStoreParameters.prototype.autoIncrement;
 
-/**
- * @const
- * @type {number}
- */
-IDBDatabaseException.QUOTA_ERR;
 
 /**
- * @const
- * @type {number}
+ * @constructor
+ * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBFactory
  */
-webkitIDBDatabaseException.QUOTA_ERR;
+function IDBFactory() {}
 
 /**
- * @const
- * @type {number}
+ * @param {string} name The name of the database to open.
+ * @param {number=} opt_version The version at which to open the database.
+ * @return {!IDBOpenDBRequest} The IDBRequest object.
  */
-IDBDatabaseException.prototype.code;
+IDBFactory.prototype.open = function(name, opt_version) {};
 
 /**
- * @const
- * @type {number}
+ * @param {string} name The name of the database to delete.
+ * @return {!IDBOpenDBRequest} The IDBRequest object.
  */
-webkitIDBDatabaseException.prototype.code;
+IDBFactory.prototype.deleteDatabase = function(name) {};
 
 /**
- * @const
- * @type {string}
+ * @param {*} first
+ * @param {*} second
+ * @return {number}
  */
-IDBDatabaseException.prototype.message;
+IDBFactory.prototype.cmp = function(first, second) {};
 
-/**
- * @const
- * @type {string}
- */
-webkitIDBDatabaseException.prototype.message;
 
 /**
  * @constructor
+ * @template T
  * @implements {EventTarget}
  * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBRequest
+ * @see https://www.w3.org/TR/IndexedDB-2/#request-api
  */
 function IDBRequest() {}
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-IDBRequest.prototype.addEventListener =
-    function(type, listener, opt_useCapture) {};
+/** @override */
+IDBRequest.prototype.addEventListener = function(type, listener, opt_options) {
+};
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-IDBRequest.prototype.removeEventListener =
-    function(type, listener, opt_useCapture) {};
+/** @override */
+IDBRequest.prototype.removeEventListener = function(
+    type, listener, opt_options) {};
 
-/**
- * @override
- * @return {boolean}
- */
+/** @override */
 IDBRequest.prototype.dispatchEvent = function(evt) {};
 
 /**
- * @constructor
- * @extends {IDBRequest}
- * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBRequest
- */
-function webkitIDBRequest() {}
-
-/**
- * @type {number}
- * @const
- */
-IDBRequest.LOADING;
-
-/**
- * @type {number}
- * @const
- */
-webkitIDBRequest.LOADING;
-
-/**
- * @type {number}
- * @const
- */
-IDBRequest.DONE;
-
-/**
- * @type {number}
- * @const
- */
-webkitIDBRequest.DONE;
-
-/**
- * @type {number}
+ * @type {!IDBRequestReadyState}
  */
 IDBRequest.prototype.readyState; // readonly
 
@@ -303,7 +162,7 @@ IDBRequest.prototype.onsuccess = function(e) {};
  */
 IDBRequest.prototype.onerror = function(e) {};
 
-/** @type {*} */
+/** @type {T} */
 IDBRequest.prototype.result;  // readonly
 
 /**
@@ -313,15 +172,16 @@ IDBRequest.prototype.result;  // readonly
 IDBRequest.prototype.errorCode;  // readonly
 
 
-/** @type {!DOMError} */
+/** @type {?DOMError|?DOMException} */
 IDBRequest.prototype.error; // readonly
 
-/** @type {Object} */
+/** @type {?IDBObjectStore|?IDBIndex|?IDBCursor} */
 IDBRequest.prototype.source; // readonly
 
-/** @type {IDBTransaction} */
+/** @type {?IDBTransaction} */
 IDBRequest.prototype.transaction; // readonly
 
+
 /**
  * @constructor
  * @extends {IDBRequest}
@@ -339,40 +199,33 @@ IDBOpenDBRequest.prototype.onblocked = function(e) {};
  */
 IDBOpenDBRequest.prototype.onupgradeneeded = function(e) {};
 
+
 /**
  * @constructor
  * @implements {EventTarget}
  * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBDatabase
+ * @see https://www.w3.org/TR/IndexedDB-2/#database-interface
  */
 function IDBDatabase() {}
 
 /**
- * @type {string}
- * @const
+ * @const {string}
  */
 IDBDatabase.prototype.name;
 
 /**
- * @type {string}
- * @const
- */
-IDBDatabase.prototype.description;
-
-/**
- * @type {string}
- * @const
+ * @const {number}
  */
 IDBDatabase.prototype.version;
 
 /**
- * @type {DOMStringList}
- * @const
+ * @const {!DOMStringList}
  */
 IDBDatabase.prototype.objectStoreNames;
 
 /**
  * @param {string} name The name of the object store.
- * @param {Object=} opt_parameters Parameters to be passed
+ * @param {!IDBObjectStoreParameters=} opt_parameters Parameters to be passed
  *     creating the object store.
  * @return {!IDBObjectStore} The created/open object store.
  */
@@ -386,15 +239,9 @@ IDBDatabase.prototype.createObjectStore =
 IDBDatabase.prototype.deleteObjectStore = function(name) {};
 
 /**
- * @param {string} version The new version of the database.
- * @return {!IDBRequest} The IDBRequest object.
- */
-IDBDatabase.prototype.setVersion = function(version) {};
-
-/**
- * @param {string|Array<string>} storeNames The stores to open in this
- *     transaction.
- * @param {(number|string)=} mode The mode for opening the object stores.
+ * @param {(string|!Array<string>|!DOMStringList)} storeNames The stores to open
+ *     in this transaction.
+ * @param {!IDBTransactionMode=} mode The mode for opening the object stores.
  * @return {!IDBTransaction} The IDBRequest object.
  */
 IDBDatabase.prototype.transaction = function(storeNames, mode) {};
@@ -406,54 +253,52 @@ IDBDatabase.prototype.transaction = function(storeNames, mode) {};
 IDBDatabase.prototype.close = function() {};
 
 /**
- * @type {Function}
+ * @type {?function(!Event)}
  */
-IDBDatabase.prototype.onabort = function() {};
+IDBDatabase.prototype.onabort;
 
 /**
- * @type {Function}
+ * @type {?function(!Event)}
  */
-IDBDatabase.prototype.onerror = function() {};
+IDBDatabase.prototype.onclose;
 
 /**
- * @type {Function}
+ * @type {?function(!Event)}
  */
-IDBDatabase.prototype.onversionchange = function() {};
+IDBDatabase.prototype.onerror;
 
 /**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
+ * @type {?function(!IDBVersionChangeEvent)}
  */
-IDBDatabase.prototype.addEventListener =
-    function(type, listener, opt_useCapture) {};
+IDBDatabase.prototype.onversionchange;
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-IDBDatabase.prototype.removeEventListener =
-    function(type, listener, opt_useCapture) {};
+/** @override */
+IDBDatabase.prototype.addEventListener = function(type, listener, opt_options) {
+};
 
-/**
- * @override
- * @return {boolean}
- */
+/** @override */
+IDBDatabase.prototype.removeEventListener = function(
+    type, listener, opt_options) {};
+
+/** @override */
 IDBDatabase.prototype.dispatchEvent = function(evt) {};
 
+
 /**
  * Typedef for valid key types according to the w3 specification. Note that this
  * is slightly wider than what is actually allowed, as all Array elements must
  * have a valid key type.
  * @see http://www.w3.org/TR/IndexedDB/#key-construct
- * @typedef {number|string|!Date|!Array<?>}
+ * @see https://www.w3.org/TR/IndexedDB-2/#key-construct
+ * @typedef {number|string|!Date|!Array<?>|!BufferSource}
  */
 var IDBKeyType;
 
+
 /**
  * @constructor
  * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBObjectStore
+ * @see https://www.w3.org/TR/IndexedDB-2/#object-store-interface
  */
 function IDBObjectStore() {}
 
@@ -463,16 +308,16 @@ function IDBObjectStore() {}
 IDBObjectStore.prototype.name;
 
 /**
- * @type {string}
+ * @type {*}
  */
 IDBObjectStore.prototype.keyPath;
 
 /**
- * @type {DOMStringList}
+ * @type {!DOMStringList}
  */
 IDBObjectStore.prototype.indexNames;
 
-/** @type {IDBTransaction} */
+/** @type {!IDBTransaction} */
 IDBObjectStore.prototype.transaction;
 
 /** @type {boolean} */
@@ -480,26 +325,26 @@ IDBObjectStore.prototype.autoIncrement;
 
 /**
  * @param {*} value The value to put into the object store.
- * @param {IDBKeyType=} key The key of this value.
+ * @param {!IDBKeyType=} key The key of this value.
  * @return {!IDBRequest} The IDBRequest object.
  */
 IDBObjectStore.prototype.put = function(value, key) {};
 
 /**
  * @param {*} value The value to add into the object store.
- * @param {IDBKeyType=} key The key of this value.
+ * @param {!IDBKeyType=} key The key of this value.
  * @return {!IDBRequest} The IDBRequest object.
  */
 IDBObjectStore.prototype.add = function(value, key) {};
 
 /**
- * @param {IDBKeyType} key The key of this value.
+ * @param {!IDBKeyType|!IDBKeyRange} key The key of this value.
  * @return {!IDBRequest} The IDBRequest object.
  */
 IDBObjectStore.prototype.delete = function(key) {};
 
 /**
- * @param {IDBKeyType|!IDBKeyRange} key The key of the document to retrieve.
+ * @param {!IDBKeyType|!IDBKeyRange} key The key of the document to retrieve.
  * @return {!IDBRequest} The IDBRequest object.
  */
 IDBObjectStore.prototype.get = function(key) {};
@@ -510,8 +355,9 @@ IDBObjectStore.prototype.get = function(key) {};
 IDBObjectStore.prototype.clear = function() {};
 
 /**
- * @param {IDBKeyRange=} range The range of the cursor.
- * @param {(number|string)=} direction The direction of cursor enumeration.
+ * @param {?IDBKeyRange=} range The range of the cursor.
+ *     Nullable because IE <11 has problems with undefined.
+ * @param {!IDBCursorDirection=} direction The direction of cursor enumeration.
  * @return {!IDBRequest} The IDBRequest object.
  */
 IDBObjectStore.prototype.openCursor = function(range, direction) {};
@@ -519,11 +365,11 @@ IDBObjectStore.prototype.openCursor = function(range, direction) {};
 /**
  * @param {string} name The name of the index.
  * @param {string|!Array<string>} keyPath The path to the index key.
- * @param {Object=} opt_parameters Optional parameters
+ * @param {!IDBIndexParameters=} opt_paramters Optional parameters
  *     for the created index.
  * @return {!IDBIndex} The IDBIndex object.
  */
-IDBObjectStore.prototype.createIndex = function(name, keyPath, opt_parameters) {};
+IDBObjectStore.prototype.createIndex = function(name, keyPath, opt_paramters) {};
 
 /**
  * @param {string} name The name of the index to retrieve.
@@ -538,150 +384,151 @@ IDBObjectStore.prototype.index = function(name) {};
 IDBObjectStore.prototype.deleteIndex = function(indexName) {};
 
 /**
- * @param {(IDBKeyType|IDBKeyRange)=} key The key of this value.
+ * @param {(!IDBKeyType|IDBKeyRange)=} key The key of this value.
  * @return {!IDBRequest} The IDBRequest object.
  * @see http://www.w3.org/TR/IndexedDB/#widl-IDBObjectStore-count
  */
 IDBObjectStore.prototype.count = function(key) {};
 
+/**
+ * @param {(!IDBKeyType|IDBKeyRange)=} query
+ * @return {!IDBRequest} The IDBRequest object.
+ * @see https://www.w3.org/TR/IndexedDB-2/#dom-idbobjectstore-getkey
+ */
+IDBObjectStore.prototype.getKey = function(query) {};
+
+/**
+ * @param {(!IDBKeyType|IDBKeyRange)=} query
+ * @param {number=} count
+ * @return {!IDBRequest} The IDBRequest object.
+ * @see https://www.w3.org/TR/IndexedDB-2/#dom-idbobjectstore-getall
+ */
+IDBObjectStore.prototype.getAll = function(query, count) {};
+
+/**
+ * @param {(!IDBKeyType|IDBKeyRange)=} query
+ * @param {number=} count
+ * @return {!IDBRequest} The IDBRequest object.
+ * @see https://www.w3.org/TR/IndexedDB-2/#dom-idbobjectstore-getallkeys
+ */
+IDBObjectStore.prototype.getAllKeys = function(query, count) {};
+
+/**
+ * @param {(!IDBKeyType|IDBKeyRange)=} query
+ * @param {!IDBCursorDirection=} direction
+ * @return {!IDBRequest} The IDBRequest object.
+ * @see https://www.w3.org/TR/IndexedDB-2/#dom-idbobjectstore-openkeycursor
+ */
+IDBObjectStore.prototype.openKeyCursor = function(query, direction) {};
+
+
 /**
  * @constructor
  * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBIndex
+ * @see https://www.w3.org/TR/IndexedDB-2/#index-interface
  */
 function IDBIndex() {}
 
 /**
  * @type {string}
- * @const
  */
 IDBIndex.prototype.name;
 
 /**
- * @type {!IDBObjectStore}
- * @const
+ * @const {!IDBObjectStore}
  */
 IDBIndex.prototype.objectStore;
 
 /**
- * @type {string}
- * @const
+ * @const {*}
  */
 IDBIndex.prototype.keyPath;
 
 /**
- * @type {boolean}
- * @const
+ * @const {boolean}
+ */
+IDBIndex.prototype.multiEntry;
+
+/**
+ * @const {boolean}
  */
 IDBIndex.prototype.unique;
 
 /**
- * @param {IDBKeyRange=} range The range of the cursor.
- * @param {(number|string)=} direction The direction of cursor enumeration.
+ * @param {(!IDBKeyType|?IDBKeyRange)=} range The range of the cursor.
+ *     Nullable because IE <11 has problems with undefined.
+ * @param {!IDBCursorDirection=} direction The direction of cursor enumeration.
  * @return {!IDBRequest} The IDBRequest object.
  */
 IDBIndex.prototype.openCursor = function(range, direction) {};
 
 /**
- * @param {IDBKeyRange=} range The range of the cursor.
- * @param {(number|string)=} direction The direction of cursor enumeration.
+ * @param {(!IDBKeyType|?IDBKeyRange)=} range The range of the cursor.
+ *     Nullable because IE <11 has problems with undefined.
+ * @param {!IDBCursorDirection=} direction The direction of cursor enumeration.
  * @return {!IDBRequest} The IDBRequest object.
  */
 IDBIndex.prototype.openKeyCursor = function(range, direction) {};
 
 /**
- * @param {IDBKeyType|!IDBKeyRange} key The id of the object to retrieve.
+ * @param {!IDBKeyType|!IDBKeyRange} key The id of the object to retrieve.
  * @return {!IDBRequest} The IDBRequest object.
  */
 IDBIndex.prototype.get = function(key) {};
 
 /**
- * @param {IDBKeyType|!IDBKeyRange} key The id of the object to retrieve.
+ * @param {!IDBKeyType|!IDBKeyRange} key The id of the object to retrieve.
  * @return {!IDBRequest} The IDBRequest object.
  */
 IDBIndex.prototype.getKey = function(key) {};
 
 /**
- * @constructor
- * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBCursor
- */
-function IDBCursor() {}
-
-/**
- * @constructor
- * @extends {IDBCursor}
- * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBCursor
- */
-function webkitIDBCursor() {}
-
-/**
- * @const
- * @type {number}
- */
-IDBCursor.NEXT;
-
-/**
- * @const
- * @type {number}
- */
-webkitIDBCursor.NEXT;
-
-/**
- * @const
- * @type {number}
+ * @param {(!IDBKeyType|!IDBKeyRange)=} query
+ * @param {number=} count
+ * @return {!IDBRequest}
+ * @see https://www.w3.org/TR/IndexedDB-2/#dom-idbindex-getall
  */
-IDBCursor.NEXT_NO_DUPLICATE;
+IDBIndex.prototype.getAll = function(query, count) {};
 
 /**
- * @const
- * @type {number}
+ * @param {(!IDBKeyType|!IDBKeyRange)=} query
+ * @param {number=} count
+ * @return {!IDBRequest}
+ * @see https://www.w3.org/TR/IndexedDB-2/#dom-idbindex-getallkeys
  */
-webkitIDBCursor.NEXT_NO_DUPLICATE;
+IDBIndex.prototype.getAllKeys = function(query, count) {};
 
 /**
- * @const
- * @type {number}
- */
-IDBCursor.PREV;
-
-/**
- * @const
- * @type {number}
+ * @param {(!IDBKeyType|!IDBKeyRange)=} opt_key
+ * @return {!IDBRequest}
  */
-webkitIDBCursor.PREV;
+IDBIndex.prototype.count = function(opt_key) {};
 
-/**
- * @const
- * @type {number}
- */
-IDBCursor.PREV_NO_DUPLICATE;
 
 /**
- * @const
- * @type {number}
+ * @constructor
+ * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBCursor
+ * @see https://www.w3.org/TR/IndexedDB-2/#cursor-interface
  */
-webkitIDBCursor.PREV_NO_DUPLICATE;
+function IDBCursor() {}
 
 /**
- * @type {*}
- * @const
+ * @const {(!IDBObjectStore|!IDBIndex)}
  */
 IDBCursor.prototype.source;
 
 /**
- * @type {number}
- * @const
+ * @const {!IDBCursorDirection}
  */
 IDBCursor.prototype.direction;
 
 /**
- * @type {IDBKeyType}
- * @const
+ * @const {!IDBKeyType}
  */
 IDBCursor.prototype.key;
 
 /**
- * @type {number}
- * @const
+ * @const {!IDBKeyType}
  */
 IDBCursor.prototype.primaryKey;
 
@@ -693,12 +540,20 @@ IDBCursor.prototype.update = function(value) {};
 
 /**
  * Note: Must be quoted to avoid parse error.
- * @param {IDBKeyType=} key Continue enumerating the cursor from the specified
+ * @param {!IDBKeyType=} key Continue enumerating the cursor from the specified
  *     key (or next).
  * @return {undefined}
  */
 IDBCursor.prototype.continue = function(key) {};
 
+/**
+ * @param {!IDBKeyType} key
+ * @param {!IDBKeyType} primaryKey
+ * @return {undefined}
+ * @see https://www.w3.org/TR/IndexedDB-2/#dom-idbcursor-continueprimarykey
+ */
+IDBCursor.prototype.continuePrimaryKey = function(key, primaryKey) {};
+
 /**
  * @param {number} count Number of times to iterate the cursor.
  * @return {undefined}
@@ -711,6 +566,7 @@ IDBCursor.prototype.advance = function(count) {};
  */
 IDBCursor.prototype.delete = function() {};
 
+
 /**
  * @constructor
  * @extends {IDBCursor}
@@ -721,66 +577,33 @@ function IDBCursorWithValue() {}
 /** @type {*} */
 IDBCursorWithValue.prototype.value; // readonly
 
-/**
- * @constructor
- * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBTransaction
- */
-function IDBTransaction() {}
 
 /**
  * @constructor
- * @extends {IDBTransaction}
  * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBTransaction
+ * @see https://www.w3.org/TR/IndexedDB-2/#transaction
  */
-function webkitIDBTransaction() {}
-
-/**
- * @const
- * @type {number}
- */
-IDBTransaction.READ_WRITE;
-
-/**
- * @const
- * @type {number}
- */
-webkitIDBTransaction.READ_WRITE;
-
-/**
- * @const
- * @type {number}
- */
-IDBTransaction.READ_ONLY;
-
-/**
- * @const
- * @type {number}
- */
-webkitIDBTransaction.READ_ONLY;
+function IDBTransaction() {}
 
 /**
- * @const
- * @type {number}
+ * @const {!DOMStringList}
  */
-IDBTransaction.VERSION_CHANGE;
+IDBTransaction.prototype.objectStoreNames;
 
 /**
- * @const
- * @type {number}
+ * @const {!IDBTransactionMode}
  */
-webkitIDBTransaction.VERSION_CHANGE;
+IDBTransaction.prototype.mode;
 
 /**
- * @type {number|string}
- * @const
+ * @const {!IDBDatabase}
  */
-IDBTransaction.prototype.mode;
+IDBTransaction.prototype.db;
 
 /**
- * @type {IDBDatabase}
- * @const
+ * @type {!DOMError|!DOMException}
  */
-IDBTransaction.prototype.db;
+IDBTransaction.prototype.error;
 
 /**
  * @param {string} name The name of the object store to retrieve.
@@ -795,100 +618,77 @@ IDBTransaction.prototype.objectStore = function(name) {};
 IDBTransaction.prototype.abort = function() {};
 
 /**
- * @type {Function}
+ * Commits the transaction.
+ * @return {undefined}
  */
-IDBTransaction.prototype.onabort = function() {};
+IDBTransaction.prototype.commit = function() {};
 
 /**
- * @type {Function}
+ * @type {?function(!Event)}
  */
-IDBTransaction.prototype.oncomplete = function() {};
+IDBTransaction.prototype.onabort;
 
 /**
- * @type {Function}
+ * @type {?function(!Event)}
  */
-IDBTransaction.prototype.onerror = function() {};
+IDBTransaction.prototype.oncomplete;
 
 /**
- * @constructor
- * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBKeyRange
+ * @type {?function(!Event)}
  */
-function IDBKeyRange() {}
+IDBTransaction.prototype.onerror;
+
 
 /**
  * @constructor
- * @extends {IDBKeyRange}
  * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBKeyRange
+ * @see https://www.w3.org/TR/IndexedDB-2/#keyrange
  */
-function webkitIDBKeyRange() {}
+function IDBKeyRange() {}
 
 /**
- * @type {*}
- * @const
+ * @const {*}
  */
 IDBKeyRange.prototype.lower;
 
 /**
- * @type {*}
- * @const
+ * @const {*}
  */
 IDBKeyRange.prototype.upper;
 
 /**
- * @type {*}
- * @const
+ * @const {boolean}
  */
 IDBKeyRange.prototype.lowerOpen;
 
 /**
- * @type {*}
- * @const
+ * @const {boolean}
  */
 IDBKeyRange.prototype.upperOpen;
 
 /**
- * @param {IDBKeyType} value The single key value of this range.
+ * @param {!IDBKeyType} value The single key value of this range.
  * @return {!IDBKeyRange} The key range.
  */
 IDBKeyRange.only = function(value) {};
 
 /**
- * @param {IDBKeyType} value The single key value of this range.
- * @return {!IDBKeyRange} The key range.
- */
-webkitIDBKeyRange.only = function(value) {};
-
-/**
- * @param {IDBKeyType} bound Creates a lower bound key range.
+ * @param {!IDBKeyType} bound Creates a lower bound key range.
  * @param {boolean=} open Open the key range.
  * @return {!IDBKeyRange} The key range.
  */
 IDBKeyRange.lowerBound = function(bound, open) {};
 
 /**
- * @param {IDBKeyType} bound Creates a lower bound key range.
- * @param {boolean=} open Open the key range.
- * @return {!IDBKeyRange} The key range.
- */
-webkitIDBKeyRange.lowerBound = function(bound, open) {};
-
-/**
- * @param {IDBKeyType} bound Creates an upper bound key range.
+ * @param {!IDBKeyType} bound Creates an upper bound key range.
  * @param {boolean=} open Open the key range.
  * @return {!IDBKeyRange} The key range.
  */
 IDBKeyRange.upperBound = function(bound, open) {};
 
 /**
- * @param {IDBKeyType} bound Creates an upper bound key range.
- * @param {boolean=} open Open the key range.
- * @return {!IDBKeyRange} The key range.
- */
-webkitIDBKeyRange.upperBound = function(bound, open) {};
-
-/**
- * @param {IDBKeyType} left The left bound value.
- * @param {IDBKeyType} right The right bound value.
+ * @param {!IDBKeyType} left The left bound value.
+ * @param {!IDBKeyType} right The right bound value.
  * @param {boolean=} openLeft Whether the left bound value should be excluded.
  * @param {boolean=} openRight Whether the right bound value should be excluded.
  * @return {!IDBKeyRange} The key range.
@@ -896,42 +696,28 @@ webkitIDBKeyRange.upperBound = function(bound, open) {};
 IDBKeyRange.bound = function(left, right, openLeft, openRight) {};
 
 /**
- * @param {IDBKeyType} left The left bound value.
- * @param {IDBKeyType} right The right bound value.
- * @param {boolean=} openLeft Whether the left bound value should be excluded.
- * @param {boolean=} openRight Whether the right bound value should be excluded.
- * @return {!IDBKeyRange} The key range.
+ * @param {!IDBKeyType} key
+ * @return {boolean}
+ * @see https://www.w3.org/TR/IndexedDB-2/#dom-idbkeyrange-includes
  */
-webkitIDBKeyRange.bound = function(left, right, openLeft, openRight) {};
+IDBKeyRange.prototype.includes = function(key) {};
+
 
 /**
+ * @param {string} type
+ * @param {!IDBVersionChangeEventInit=} opt_eventInit
  * @constructor
  * @extends {Event}
  * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBVersionChangeEvent
  */
-function IDBVersionChangeEvent() {}
+function IDBVersionChangeEvent(type, opt_eventInit) {}
 
 /**
- * @type {number}
- * @const
+ * @const {number}
  */
 IDBVersionChangeEvent.prototype.oldVersion;
 
 /**
- * @type {?number}
- * @const
+ * @const {?number}
  */
 IDBVersionChangeEvent.prototype.newVersion;
-
-/**
- * @constructor
- * @extends {IDBVersionChangeEvent}
- * @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBVersionChangeEvent
- */
-function webkitIDBVersionChangeEvent() {}
-
-/**
- * @type {string}
- * @const
- */
-webkitIDBVersionChangeEvent.prototype.version;
diff --git a/javascript/externs/web/w3c_navigation_timing.js b/javascript/externs/web/w3c_navigation_timing.js
index 04d4f03cceb8..aaf1423c1f49 100644
--- a/javascript/externs/web/w3c_navigation_timing.js
+++ b/javascript/externs/web/w3c_navigation_timing.js
@@ -58,6 +58,7 @@ function PerformanceEntry() {}
 /** @type {number} */ PerformanceEntry.prototype.duration;
 
 /**
+ * https://www.w3.org/TR/resource-timing-2/#performanceresourcetiming
  * @constructor
  * @extends {PerformanceEntry}
  */
@@ -75,27 +76,138 @@ PerformanceResourceTiming.prototype.secureConnectionStart;
 /** @type {number} */ PerformanceResourceTiming.prototype.responseStart;
 /** @type {number} */ PerformanceResourceTiming.prototype.responseEnd;
 /** @type {string} */ PerformanceResourceTiming.prototype.initiatorType;
+/** @type {number|undefined} */
+PerformanceResourceTiming.prototype.transferSize;
+/** @type {number|undefined} */
+PerformanceResourceTiming.prototype.encodedBodySize;
+/** @type {number|undefined} */
+PerformanceResourceTiming.prototype.decodedBodySize;
+/** @type {number|undefined} */
+PerformanceResourceTiming.prototype.workerStart;
+/** @type {string} */ PerformanceResourceTiming.prototype.nextHopProtocol;
+
+/**
+ * Possible values are 'navigate', 'reload', 'back_forward', and 'prerender'.
+ * See https://w3c.github.io/navigation-timing/#sec-performance-navigation-types
+ * @typedef {string}
+ */
+var NavigationType;
+
+/**
+ * https://w3c.github.io/navigation-timing/#sec-PerformanceNavigationTiming
+ * @constructor
+ * @extends {PerformanceResourceTiming}
+ */
+function PerformanceNavigationTiming() {}
+/** @type {number} */ PerformanceNavigationTiming.prototype.unloadEventStart;
+/** @type {number} */ PerformanceNavigationTiming.prototype.unloadEventEnd;
+/** @type {number} */ PerformanceNavigationTiming.prototype.domInteractive;
+/** @type {number} */ PerformanceNavigationTiming.prototype
+    .domContentLoadedEventStart;
+/** @type {number} */ PerformanceNavigationTiming.prototype
+    .domContentLoadedEventEnd;
+/** @type {number} */ PerformanceNavigationTiming.prototype.domComplete;
+/** @type {number} */ PerformanceNavigationTiming.prototype.loadEventStart;
+/** @type {number} */ PerformanceNavigationTiming.prototype.loadEventEnd;
+/** @type {NavigationType} */ PerformanceNavigationTiming.prototype.type;
+/** @type {number} */ PerformanceNavigationTiming.prototype.redirectCount;
+
+/**
+ * https://w3c.github.io/paint-timing/#sec-PerformancePaintTiming
+ * @constructor
+ * @extends {PerformanceEntry}
+ */
+function PerformancePaintTiming() {}
 
 /** @constructor */
 function PerformanceNavigation() {}
-/** @type {number} */ PerformanceNavigation.prototype.TYPE_NAVIGATE = 0;
-/** @type {number} */ PerformanceNavigation.prototype.TYPE_RELOAD = 1;
-/** @type {number} */ PerformanceNavigation.prototype.TYPE_BACK_FORWARD = 2;
-/** @type {number} */ PerformanceNavigation.prototype.TYPE_RESERVED = 255;
+/** @const {number} */ PerformanceNavigation.TYPE_NAVIGATE;
+/** @const {number} */ PerformanceNavigation.prototype.TYPE_NAVIGATE;
+/** @const {number} */ PerformanceNavigation.TYPE_RELOAD;
+/** @const {number} */ PerformanceNavigation.prototype.TYPE_RELOAD;
+/** @const {number} */ PerformanceNavigation.TYPE_BACK_FORWARD;
+/** @const {number} */ PerformanceNavigation.prototype.TYPE_BACK_FORWARD;
+/** @const {number} */ PerformanceNavigation.TYPE_RESERVED;
+/** @const {number} */ PerformanceNavigation.prototype.TYPE_RESERVED;
 /** @type {number} */ PerformanceNavigation.prototype.type;
 /** @type {number} */ PerformanceNavigation.prototype.redirectCount;
 
-// Only available in WebKit, and only with the --enable-memory-info flag.
-/** @constructor */
-function PerformanceMemory() {}
-/** @type {number} */ PerformanceMemory.prototype.jsHeapSizeLimit;
-/** @type {number} */ PerformanceMemory.prototype.totalJSHeapSize;
-/** @type {number} */ PerformanceMemory.prototype.usedJSHeapSize;
+/**
+ * https://w3c.github.io/longtasks/#taskattributiontiming
+ * @constructor
+ * @extends {PerformanceEntry}
+ */
+function TaskAttributionTiming() {}
+/** @type {string} */ TaskAttributionTiming.prototype.containerId;
+/** @type {string} */ TaskAttributionTiming.prototype.containerName;
+/** @type {string} */ TaskAttributionTiming.prototype.containerSrc;
+/** @type {string} */ TaskAttributionTiming.prototype.containerType;
+
+/**
+ * https://w3c.github.io/longtasks/#performancelongtasktiming
+ * @constructor
+ * @extends {PerformanceEntry}
+ */
+function PerformanceLongTaskTiming() {}
+/** @type {!Array<!TaskAttributionTiming>} */
+PerformanceLongTaskTiming.prototype.attribution;
+
+/**
+ * https://wicg.github.io/layout-instability/#sec-layout-shift
+ * @constructor
+ * @extends {PerformanceEntry}
+ */
+function LayoutShift() {}
+/** @type {number} */ LayoutShift.prototype.value;
+/** @type {boolean} */ LayoutShift.prototype.hadRecentInput;
+/** @type {number} */ LayoutShift.prototype.lastInputTime;
+/** @type {!Array<!LayoutShiftAttribution>} */ LayoutShift.prototype.sources;
+
+/**
+ * https://wicg.github.io/layout-instability/#sec-layout-shift
+ * @constructor
+ */
+function LayoutShiftAttribution() {}
+/** @type {?Node} */ LayoutShiftAttribution.prototype.node;
+/** @type {!DOMRectReadOnly} */ LayoutShiftAttribution.prototype.previousRect;
+/** @type {!DOMRectReadOnly} */ LayoutShiftAttribution.prototype.currentRect;
+
+/**
+ * https://wicg.github.io/largest-contentful-paint/#largestcontentfulpaint
+ * @constructor
+ * @extends {PerformanceEntry}
+ */
+function LargestContentfulPaint() {}
+/** @type {number} */ LargestContentfulPaint.prototype.renderTime;
+/** @type {number} */ LargestContentfulPaint.prototype.loadTime;
+/** @type {number} */ LargestContentfulPaint.prototype.size;
+/** @type {string} */ LargestContentfulPaint.prototype.id;
+/** @type {string} */ LargestContentfulPaint.prototype.url;
+/** @type {?Element} */ LargestContentfulPaint.prototype.element;
+
+/**
+ * https://wicg.github.io/event-timing/#sec-performance-event-timing
+ * @constructor
+ * @extends {PerformanceEntry}
+ */
+function PerformanceEventTiming() {}
+/** @type {number} */ PerformanceEventTiming.prototype.processingStart;
+/** @type {number} */ PerformanceEventTiming.prototype.processingEnd;
+/** @type {boolean} */ PerformanceEventTiming.prototype.cancelable;
+/** @type {?Node} */ PerformanceEventTiming.prototype.target;
 
 /** @constructor */
 function Performance() {}
-/** @type {PerformanceTiming} */ Performance.prototype.timing;
-/** @type {PerformanceNavigation} */ Performance.prototype.navigation;
+
+/** @type {PerformanceTiming} */
+Performance.prototype.timing;
+
+/** @type {PerformanceNavigation} */
+Performance.prototype.navigation;
+
+/** @type {number} */
+Performance.prototype.timeOrigin;
+
 
 /**
  * Clears the buffer used to store the current list of
@@ -105,10 +217,10 @@ function Performance() {}
 Performance.prototype.clearResourceTimings = function() {};
 
 /**
- * Clear out the buffer of performance timing events for webkit browsers.
- * @return {undefined}
+ * A callback that is invoked when the resourcetimingbufferfull event is fired.
+ * @type {?function(Event)}
  */
-Performance.prototype.webkitClearResourceTimings = function() {};
+Performance.prototype.onresourcetimingbufferfull = function() {};
 
 /**
  * Set the maximum number of PerformanceResourceTiming resources that may be
@@ -119,46 +231,37 @@ Performance.prototype.webkitClearResourceTimings = function() {};
 Performance.prototype.setResourceTimingBufferSize = function(maxSize) {};
 
 /**
- * @return {Array<PerformanceEntry>} A copy of the PerformanceEntry list,
+ * @return {!Array<!PerformanceEntry>} A copy of the PerformanceEntry list,
  *     in chronological order with respect to startTime.
  * @nosideeffects
  */
 Performance.prototype.getEntries = function() {};
 
 /**
- * @param {string} entryType Only return {@code PerformanceEntry}s with this
+ * @param {string} entryType Only return `PerformanceEntry`s with this
  *     entryType.
- * @return {Array<PerformanceEntry>} A copy of the PerformanceEntry list,
+ * @return {!Array<!PerformanceEntry>} A copy of the PerformanceEntry list,
  *     in chronological order with respect to startTime.
  * @nosideeffects
  */
 Performance.prototype.getEntriesByType = function(entryType) {};
 
 /**
- * @param {string} name Only return {@code PerformanceEntry}s with this name.
- * @param {string=} opt_entryType Only return {@code PerformanceEntry}s with
+ * @param {string} name Only return `PerformanceEntry`s with this name.
+ * @param {string=} opt_entryType Only return `PerformanceEntry`s with
  *     this entryType.
- * @return {Array<PerformanceEntry>} PerformanceEntry list in chronological
+ * @return {!Array<!PerformanceEntry>} PerformanceEntry list in chronological
  *     order with respect to startTime.
  * @nosideeffects
  */
 Performance.prototype.getEntriesByName = function(name, opt_entryType) {};
 
-// Only available in WebKit, and only with the --enable-memory-info flag.
-/** @type {PerformanceMemory} */ Performance.prototype.memory;
-
 /**
  * @return {number}
  * @nosideeffects
  */
 Performance.prototype.now = function() {};
 
-/**
- * @return {number}
- * @nosideeffects
- */
-Performance.prototype.webkitNow = function() {};
-
 /**
  * @param {string} markName
  * @return {undefined}
@@ -177,8 +280,8 @@ Performance.prototype.clearMarks = function(opt_markName) {};
  * @param {string=} opt_endMark
  * @return {undefined}
  */
-Performance.prototype.measure =
-    function(measureName, opt_startMark, opt_endMark) {};
+Performance.prototype.measure = function(
+    measureName, opt_startMark, opt_endMark) {};
 
 /**
  * @param {string=} opt_measureName
@@ -194,3 +297,73 @@ Window.prototype.performance;
  * @suppress {duplicate}
  */
 var performance;
+
+/**
+ * @constructor
+ * @extends {Performance}
+ */
+function WorkerPerformance() {}
+
+/**
+ * @typedef {function(!PerformanceObserverEntryList, !PerformanceObserver): void}
+ */
+var PerformanceObserverCallback;
+
+/**
+ * See:
+ * https://w3c.github.io/performance-timeline/#the-performanceobserver-interface
+ * @constructor
+ * @param {!PerformanceObserverCallback} callback
+ */
+function PerformanceObserver(callback) {}
+
+/**
+ * @param {!PerformanceObserverInit} options
+ */
+PerformanceObserver.prototype.observe = function(options) {};
+
+/** @return {void} */
+PerformanceObserver.prototype.disconnect = function() {};
+
+/**
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/PerformanceObserver/takeRecords
+ * @see https://www.w3.org/TR/performance-timeline-2/#takerecords-method
+ * @return {!Array<!PerformanceEntry>} The current PerformanceEntry list stored
+ *     in the performance observer buffer, emptying it out.
+ */
+PerformanceObserver.prototype.takeRecords = function() {};
+
+/** @const {!Array<string>} */
+PerformanceObserver.prototype.supportedEntryTypes;
+
+/**
+ * @record
+ */
+function PerformanceObserverInit() {}
+
+/** @type {undefined|!Array<string>} */
+PerformanceObserverInit.prototype.entryTypes;
+/** @type {undefined|string} */
+PerformanceObserverInit.prototype.type;
+/** @type {undefined|boolean} */
+PerformanceObserverInit.prototype.buffered;
+
+/**
+ * @constructor
+ */
+function PerformanceObserverEntryList() {}
+
+/** @return {!Array<!PerformanceEntry>} */
+PerformanceObserverEntryList.prototype.getEntries = function() {};
+/**
+ * @param {string} type
+ * @return {!Array<!PerformanceEntry>}
+ */
+PerformanceObserverEntryList.prototype.getEntriesByName = function(type) {};
+/**
+ * @param {string} name
+ * @param {string=} opt_type
+ * @return {!Array<!PerformanceEntry>}
+ */
+PerformanceObserverEntryList.prototype.getEntriesByType = function(
+    name, opt_type) {};
diff --git a/javascript/externs/web/w3c_permissions.js b/javascript/externs/web/w3c_permissions.js
index 007f63d3a4f7..58e5a071f10b 100644
--- a/javascript/externs/web/w3c_permissions.js
+++ b/javascript/externs/web/w3c_permissions.js
@@ -78,27 +78,15 @@ PermissionStatus.prototype.status;
 /** @type {?function(!Event)} */
 PermissionStatus.prototype.onchange;
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-PermissionStatus.prototype.addEventListener = function(type,
-                                                       listener,
-                                                       opt_useCapture) {};
+/** @override */
+PermissionStatus.prototype.addEventListener = function(
+    type, listener, opt_options) {};
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-PermissionStatus.prototype.removeEventListener = function(type,
-                                                          listener,
-                                                          opt_useCapture) {};
-/**
- * @override
- * @return {boolean}
- */
+/** @override */
+PermissionStatus.prototype.removeEventListener = function(
+    type, listener, opt_options) {};
+
+/** @override */
 PermissionStatus.prototype.dispatchEvent = function(evt) {};
 
 
diff --git a/javascript/externs/web/w3c_pointer_events.js b/javascript/externs/web/w3c_pointer_events.js
index 772b3fec3be8..41cbb5ca8d8a 100644
--- a/javascript/externs/web/w3c_pointer_events.js
+++ b/javascript/externs/web/w3c_pointer_events.js
@@ -42,6 +42,26 @@ Navigator.prototype.pointerEnabled;
 Navigator.prototype.maxTouchPoints;
 
 
+/**
+ * @param {number} pointerId
+ * @see https://www.w3.org/TR/pointerevents/#widl-Element-setPointerCapture-void-long-pointerId
+ */
+Element.prototype.setPointerCapture = function(pointerId) {};
+
+/**
+ * @param {number} pointerId
+ * @see https://www.w3.org/TR/pointerevents/#widl-Element-releasePointerCapture-void-long-pointerId
+ */
+Element.prototype.releasePointerCapture = function(pointerId) {};
+
+/**
+ * @param {number} pointerId
+ * @see https://www.w3.org/TR/pointerevents/#dom-element-haspointercapture
+ * @return {boolean}
+ */
+Element.prototype.hasPointerCapture = function(pointerId) {};
+
+
 /**
  * @record
  * @extends {MouseEventInit}
@@ -107,11 +127,18 @@ PointerEvent.prototype.pointerType;
 PointerEvent.prototype.isPrimary;
 
 // Microsoft pointerType values
-/** @type {string} */
+/** @const {string} */
 PointerEvent.prototype.MSPOINTER_TYPE_TOUCH;
 
-/** @type {string} */
+/** @const {string} */
 PointerEvent.prototype.MSPOINTER_TYPE_PEN;
 
-/** @type {string} */
+/** @const {string} */
 PointerEvent.prototype.MSPOINTER_TYPE_MOUSE;
+
+/**
+ * @see https://w3c.github.io/pointerevents/extension.html
+ * @return {!Array<!PointerEvent>}
+ */
+PointerEvent.prototype.getCoalescedEvents = function() {};
+
diff --git a/javascript/externs/web/w3c_range.js b/javascript/externs/web/w3c_range.js
index fb79fd236404..a24d217af0ec 100644
--- a/javascript/externs/web/w3c_range.js
+++ b/javascript/externs/web/w3c_range.js
@@ -32,6 +32,58 @@
  */
 function Range() {}
 
+// constants on the constructor
+
+/**
+ * @const {number}
+ * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#Level2-Range-compareHow
+ */
+Range.START_TO_START;
+
+/**
+ * @const {number}
+ * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#Level2-Range-compareHow
+ */
+Range.START_TO_END;
+
+/**
+ * @const {number}
+ * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#Level2-Range-compareHow
+ */
+Range.END_TO_END;
+
+/**
+ * @const {number}
+ * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#Level2-Range-compareHow
+ */
+Range.END_TO_START;
+
+// constants repeated on the prototype
+
+/**
+ * @const {number}
+ * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#Level2-Range-compareHow
+ */
+Range.prototype.START_TO_START;
+
+/**
+ * @const {number}
+ * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#Level2-Range-compareHow
+ */
+Range.prototype.START_TO_END;
+
+/**
+ * @const {number}
+ * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#Level2-Range-compareHow
+ */
+Range.prototype.END_TO_END;
+
+/**
+ * @const {number}
+ * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#Level2-Range-compareHow
+ */
+Range.prototype.END_TO_START;
+
 /**
  * @type {Node}
  * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#Level-2-Range-attr-startParent
@@ -133,30 +185,6 @@ Range.prototype.selectNode = function(refNode) {};
  */
 Range.prototype.selectNodeContents = function(refNode) {};
 
-/**
- * @type {number}
- * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#Level2-Range-compareHow
- */
-Range.prototype.START_TO_START = 0;
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#Level2-Range-compareHow
- */
-Range.prototype.START_TO_END = 1;
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#Level2-Range-compareHow
- */
-Range.prototype.END_TO_END = 2;
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#Level2-Range-compareHow
- */
-Range.prototype.END_TO_START = 3;
-
 /**
  * @param {number} how
  * @param {Range} sourceRange
@@ -211,7 +239,7 @@ Range.prototype.detach = function() {};
 
 // Introduced in DOM Level 2:
 /**
- * @constructor
+ * @interface
  * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#Level-2-DocumentRange-idl
  */
 function DocumentRange() {}
@@ -221,28 +249,3 @@ function DocumentRange() {}
  * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#Level2-DocumentRange-method-createRange
  */
 DocumentRange.prototype.createRange = function() {};
-
-// Introduced in DOM Level 2:
-/**
- * @constructor
- * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#RangeException
- */
-function RangeException() {}
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#RangeExceptionCode
- */
-RangeException.prototype.code;
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#RangeExceptionCode
- */
-RangeException.prototype.BAD_BOUNDARYPOINTS_ERR = 1;
-
-/**
- * @type {number}
- * @see http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html#RangeExceptionCode
- */
-RangeException.prototype.INVALID_NODE_TYPE_ERR = 2;
diff --git a/javascript/externs/web/w3c_requestidlecallback.js b/javascript/externs/web/w3c_requestidlecallback.js
index b6efd141195c..5842f2fd68f4 100644
--- a/javascript/externs/web/w3c_requestidlecallback.js
+++ b/javascript/externs/web/w3c_requestidlecallback.js
@@ -33,7 +33,7 @@ var IdleCallbackOptions;
 
 /**
  * Schedules a callback to run when the browser is idle.
- * @param {function(!IdleDeadline)} callback Called when the browser is idle.
+ * @param {function(!IdleDeadline): void} callback Called when the browser is idle.
  * @param {number|IdleCallbackOptions=} opt_options If set, gives the browser a time in ms by which
  *     it must execute the callback. No timeout enforced otherwise.
  * @return {number} A handle that can be used to cancel the scheduled callback.
@@ -43,7 +43,7 @@ function requestIdleCallback(callback, opt_options) {}
 
 /**
  * Cancels a callback scheduled to run when the browser is idle.
- * @param {number} handle The handle returned by {@code requestIdleCallback} for
+ * @param {number} handle The handle returned by `requestIdleCallback` for
  *     the scheduled callback to cancel.
  * @return {undefined}
  */
@@ -53,7 +53,7 @@ function cancelIdleCallback(handle) {}
 
 /**
  * An interface for an object passed into the callback for
- * {@code requestIdleCallback} that remains up-to-date on the amount of idle
+ * `requestIdleCallback` that remains up-to-date on the amount of idle
  * time left in the current time slice.
  * @interface
  */
diff --git a/javascript/externs/web/w3c_rtc.js b/javascript/externs/web/w3c_rtc.js
index 027d33894262..3a17e6dc0beb 100644
--- a/javascript/externs/web/w3c_rtc.js
+++ b/javascript/externs/web/w3c_rtc.js
@@ -59,20 +59,17 @@ SourceInfo.prototype.facing;
 function MediaSettingsRange() {}
 
 /**
- * @type {number}
- * @const
+ * @const {number}
  */
 MediaSettingsRange.prototype.max;
 
 /**
- * @type {number}
- * @const
+ * @const {number}
  */
 MediaSettingsRange.prototype.min;
 
 /**
- * @type {number}
- * @const
+ * @const {number}
  */
 MediaSettingsRange.prototype.step;
 
@@ -304,27 +301,17 @@ MediaTrackSupportedConstraints.prototype.groupId;
 function MediaStreamTrack() {}
 
 /**
- * @param {!function(!Array<!SourceInfo>)} callback
- * @return {undefined}
- * @deprecated Use MediaDevices.enumerateDevices().
- */
-MediaStreamTrack.getSources = function(callback) {};
-
-/**
- * @type {string}
- * @const
+ * @const {string}
  */
 MediaStreamTrack.prototype.kind;
 
 /**
- * @type {string}
- * @const
+ * @const {string}
  */
 MediaStreamTrack.prototype.id;
 
 /**
- * @type {string}
- * @const
+ * @const {string}
  */
 MediaStreamTrack.prototype.label;
 
@@ -334,8 +321,7 @@ MediaStreamTrack.prototype.label;
 MediaStreamTrack.prototype.enabled;
 
 /**
- * @type {boolean}
- * @const
+ * @const {boolean}
  */
 MediaStreamTrack.prototype.muted;
 
@@ -347,8 +333,7 @@ MediaStreamTrack.prototype.muted;
 MediaStreamTrack.prototype.contentHint;
 
 /**
- * @type {boolean}
- * @const
+ * @const {boolean}
  */
 MediaStreamTrack.prototype.remote;
 
@@ -423,8 +408,7 @@ var MediaStreamTrackEventInit;
 function MediaStreamTrackEvent(type, eventInitDict) {}
 
 /**
- * @type {!MediaStreamTrack}
- * @const
+ * @const {!MediaStreamTrack}
  */
 MediaStreamTrackEvent.prototype.track;
 
@@ -457,14 +441,12 @@ MediaStream.prototype.dispatchEvent = function(evt) {};
 /**
  * TODO(bemasc): Remove this property.
  * @deprecated
- * @type {string}
- * @const
+ * @const {string}
  */
 MediaStream.prototype.label;
 
 /**
- * @type {string}
- * @const
+ * @const {string}
  */
 MediaStream.prototype.id;
 
@@ -551,13 +533,6 @@ MediaStream.prototype.onremovetrack;
  */
 MediaStream.prototype.stop = function() {};
 
-/**
- * @type {function(new: MediaStream,
- *                 (!MediaStream|!Array<!MediaStreamTrack>)=)}
- */
-var webkitMediaStream;
-
-
 /**
  * @typedef {{tone: string}}
  * @see https://www.w3.org/TR/webrtc/#dom-rtcdtmftonechangeeventinit
@@ -594,6 +569,11 @@ function RTCDTMFSender() {}
 RTCDTMFSender.prototype.insertDTMF =
     function(tones, opt_duration, opt_interToneGap) {};
 
+/**
+ * @type {?boolean}
+ */
+RTCDTMFSender.prototype.canInsertDTMF;
+
 /**
  * @type {?function(!RTCDTMFToneChangeEvent)}
  */
@@ -606,10 +586,44 @@ RTCDTMFSender.prototype.toneBuffer;
 
 
 /**
- * @interface
+ * @typedef {{
+ *   mimeType: string,
+ *   clockRate: number,
+ *   channels: (number|undefined),
+ *   sdpFmtpLine: (string|undefined),
+ * }}
+ *
+ * @see https://www.w3.org/TR/webrtc/#dom-rtcrtpcodeccapability
+ */
+var RTCRtpCodecCapability;
+
+
+/**
+ * @typedef {{
+ *   uri: string,
+ * }}
+ *
+ * @see https://www.w3.org/TR/webrtc/#dom-rtcrtpheaderextensioncapability
+ */
+var RTCRtpHeaderExtensionCapability;
+
+
+/**
+ * @typedef {{
+ *   codecs: !Array<!RTCRtpCodecCapability>,
+ *   headerExtensions: !Array<!RTCRtpHeaderExtensionCapability>,
+ * }}
+ *
+ * @see https://www.w3.org/TR/webrtc/#dom-rtcrtpcapabilities
+ */
+var RTCRtpCapabilities;
+
+
+/**
+ * @constructor
  * @see https://www.w3.org/TR/webrtc/#rtcrtpsender-interface
  */
-function RTCRtpSender(track, transport) {}
+function RTCRtpSender() {}
 
 /**
  * @const {!RTCDTMFSender}
@@ -622,24 +636,62 @@ RTCRtpSender.prototype.dtmf;
 RTCRtpSender.prototype.track;
 
 /**
- * @param {!MediaStreamTrack} track
+ * @param {?MediaStreamTrack} track
+ * @return {!Promise<void>}
+ * @see https://www.w3.org/TR/webrtc/#dom-rtcrtpsender
  */
 RTCRtpSender.prototype.replaceTrack = function(track) {};
 
 
 /**
- * @return {!Object}
+ * @return {!RTCRtpSendParameters}
  */
 RTCRtpSender.prototype.getParameters = function() {};
 
 
 /**
- * @param {!Object} params
+ * @param {!RTCRtpSendParameters} params
  * @return {!Promise<undefined>}
  */
 RTCRtpSender.prototype.setParameters = function(params) {};
 
 
+/**
+ * @return {!Promise<!RTCStatsReport>}
+ */
+RTCRtpSender.prototype.getStats = function() {};
+
+/**
+ * @param {string} kind
+ * @return {?RTCRtpCapabilities}
+ */
+RTCRtpSender.getCapabilities = function(kind) {};
+
+
+/**
+ * @record
+ * @see https://www.w3.org/TR/webrtc/#dom-rtcrtpsendparameters
+ */
+function RTCRtpSendParameters() {}
+
+/**
+ * @type {string|undefined}
+ */
+RTCRtpSendParameters.prototype.transactionId;
+
+/**
+ * @type {!Array<!RTCRtpEncodingParameters>}
+ */
+RTCRtpSendParameters.prototype.encodings;
+
+/**
+ * Possible string values are "maintain-framerate", "maintain-resolution", and
+ * "balanced".
+ * @type {string|undefined}
+ */
+RTCRtpSendParameters.prototype.degradationPreference;
+
+
 /**
  * @interface
  * @see https://www.w3.org/TR/webrtc/#dom-rtcrtpcontributingsource
@@ -652,16 +704,36 @@ function RTCRtpContributingSource() {}
 RTCRtpContributingSource.prototype.source;
 
 /**
- * @type {?Date}
+ * @type {?Date|number}
  */
 RTCRtpContributingSource.prototype.timestamp;
 
+/**
+ * @type {number|undefined}
+ */
+RTCRtpContributingSource.prototype.audioLevel;
 
 /**
- * @interface
+ * This is a relatively new field and browsers may not yet be compliant to the
+ * spec.
+ * @type {?number}
+ * @see https://w3c.github.io/webrtc-pc/#dom-rtcrtpcontributingsource-rtptimestamp
+ */
+RTCRtpContributingSource.prototype.rtpTimestamp;
+
+/**
+ * This is a relatively new field and browsers may not yet be compliant to the
+ * spec.
+ * @type {number|undefined}
+ * @see https://w3c.github.io/webrtc-extensions/#dictionary-rtcrtpcontributingsource-members
+ */
+RTCRtpContributingSource.prototype.captureTimestamp;
+
+/**
+ * @constructor
  * @see https://www.w3.org/TR/webrtc/#rtcrtpreceiver-interface
  */
-function RTCRtpReceiver(transport, kind) {}
+function RTCRtpReceiver() {}
 
 /**
  * @const {!MediaStreamTrack}
@@ -678,6 +750,28 @@ RTCRtpReceiver.prototype.getContributingSources = function() {};
  */
 RTCRtpReceiver.prototype.getSynchronizationSources = function() {};
 
+
+/**
+ * @return {!Promise<!RTCStatsReport>}
+ */
+RTCRtpReceiver.prototype.getStats = function() {};
+
+/**
+ * Chrome exclusive hint to control jitter buffer delay. Measured in seconds.
+ * @see https://henbos.github.io/webrtc-extensions/#dfn-playoutdelayhint
+ * @type {?number|undefined}
+ */
+RTCRtpReceiver.prototype.playoutDelayHint;
+
+/**
+ * Get most optimistic view of the capabilities of the system for sending media
+ * of the given kind.
+ * @see https://www.w3.org/TR/webrtc/#dom-rtcrtpreceiver-getcapabilities
+ * @param {!string} kind Media kind: 'video' or 'audio'.
+ * @return {!RTCRtpCapabilities}
+ */
+RTCRtpReceiver.getCapabilities = function(kind) {};
+
 /**
  * @see https://www.w3.org/TR/webrtc/#dom-rtcrtptransceiverinit
  * @record
@@ -729,6 +823,13 @@ RTCRtpEncodingParameters.prototype.active;
  */
 RTCRtpEncodingParameters.prototype.priority;
 
+/**
+ * Possible values are "very-low", "low" (default), "medium", and "high".
+ * @see https://w3c.github.io/webrtc-dscp-exp/
+ * @type {?string|undefined}
+ */
+RTCRtpEncodingParameters.prototype.networkPriority;
+
 /**
  * @type {?number|undefined}
  */
@@ -754,6 +855,12 @@ RTCRtpEncodingParameters.prototype.rid;
  */
 RTCRtpEncodingParameters.prototype.scaleResolutionDownBy;
 
+/**
+ * @see https://w3c.github.io/webrtc-extensions/#dom-rtcrtpencodingparameters-adaptiveptime
+ * @type {?boolean|undefined}
+ */
+RTCRtpEncodingParameters.prototype.adaptivePtime;
+
 /**
  * @interface
  * @see https://www.w3.org/TR/webrtc/#rtcrtptransceiver-interface
@@ -771,7 +878,7 @@ RTCRtpTransceiver.prototype.mid;
 RTCRtpTransceiver.prototype.stopped;
 
 /**
- * @const {!RTCRtpTransceiverDirection}
+ * @type {!RTCRtpTransceiverDirection}
  */
 RTCRtpTransceiver.prototype.direction;
 
@@ -799,6 +906,11 @@ RTCRtpTransceiver.prototype.sender;
  */
 RTCRtpTransceiver.prototype.receiver;
 
+/**
+ * @param {!Array<!RTCRtpCodecCapability>} codecs
+ */
+RTCRtpTransceiver.prototype.setCodecPreferences = function(codecs) {};
+
 /**
  * @see https://w3c.github.io/mediacapture-main/getusermedia.html#dom-longrange
  * @record
@@ -1042,11 +1154,10 @@ MediaStreamConstraints.prototype.video;
 function NavigatorUserMediaError() {}
 
 /**
- * @type {number}
+ * @const {number}
  * @deprecated Removed from the standard and some browsers.
- * @const
  */
-NavigatorUserMediaError.prototype.PERMISSION_DENIED;  /** 1 */
+NavigatorUserMediaError.prototype.PERMISSION_DENIED;
 
 /**
  * @type {number}
@@ -1073,19 +1184,6 @@ NavigatorUserMediaError.prototype.message;
  */
 NavigatorUserMediaError.prototype.constraintName;
 
-/**
- * @param {MediaStreamConstraints} constraints A MediaStreamConstraints object.
- * @param {function(!MediaStream)} successCallback
- *     A NavigatorUserMediaSuccessCallback function.
- * @param {function(!NavigatorUserMediaError)=} errorCallback A
- *     NavigatorUserMediaErrorCallback function.
- * @see http://dev.w3.org/2011/webrtc/editor/getusermedia.html
- * @see https://www.w3.org/TR/mediacapture-streams/
- * @return {undefined}
- */
-Navigator.prototype.webkitGetUserMedia =
-  function(constraints, successCallback, errorCallback) {};
-
 /**
  * @param {string} type
  * @param {!Object} eventInitDict
@@ -1094,8 +1192,7 @@ Navigator.prototype.webkitGetUserMedia =
 function MediaStreamEvent(type, eventInitDict) {}
 
 /**
- * @type {?MediaStream}
- * @const
+ * @const {?MediaStream}
  */
 MediaStreamEvent.prototype.stream;
 
@@ -1222,6 +1319,21 @@ MediaRecorder.prototype.requestData = function() {};
  */
 MediaRecorder.isTypeSupported = function(type) {};
 
+/**
+ * @constructor
+ * @extends {Event}
+ * @param {string} type
+ * @param {{data: !Blob, timecode: (number|undefined)}} eventInitDict
+ * @see https://www.w3.org/TR/mediastream-recording/#blobevent-section
+ */
+function BlobEvent(type, eventInitDict) {}
+
+/** @type {!Blob} */
+BlobEvent.prototype.data;
+
+/** @type {number} */
+BlobEvent.prototype.timecode;
+
 /**
  * @interface
  * @see https://w3c.github.io/mediacapture-image/##photosettings-section
@@ -1255,26 +1367,22 @@ PhotoSettings.prototype.redEyeReduction;
 function PhotoCapabilities() {}
 
 /**
- * @type {string}
- * @const
+ * @const {string}
  */
 PhotoCapabilities.prototype.redEyeReduction;
 
 /**
- * @type {!MediaSettingsRange}
- * @const
+ * @const {!MediaSettingsRange}
  */
 PhotoCapabilities.prototype.imageHeight;
 
 /**
- * @type {!MediaSettingsRange}
- * @const
+ * @const {!MediaSettingsRange}
  */
 PhotoCapabilities.prototype.imageWidth;
 
 /**
- * @type {!Array<!string>}
- * @const
+ * @const {!Array<string>}
  */
 PhotoCapabilities.prototype.fillLightMode;
 
@@ -1302,8 +1410,7 @@ ImageCapture.prototype.getPhotoCapabilities = function() {};
 ImageCapture.prototype.grabFrame = function() {};
 
 /**
- * @type {!MediaStreamTrack}
- * @const
+ * @const {!MediaStreamTrack}
  */
 ImageCapture.prototype.track;
 
@@ -1316,26 +1423,22 @@ ImageCapture.prototype.track;
 function RTCTrackEvent(type, eventInitDict) {}
 
 /**
- * @type {?RTCRtpReceiver}
- * @const
+ * @const {!RTCRtpReceiver}
  */
 RTCTrackEvent.prototype.receiver;
 
 /**
- * @type {?MediaStreamTrack}
- * @const
+ * @const {!MediaStreamTrack}
  */
 RTCTrackEvent.prototype.track;
 
 /**
- * @type {?Array<!MediaStream>}
- * @const
+ * @const {!Array<!MediaStream>}
  */
 RTCTrackEvent.prototype.streams;
 
 /**
- * @type {?RTCRtpTransceiver}
- * @const
+ * @const {!RTCRtpTransceiver}
  */
 RTCTrackEvent.prototype.transceiver;
 
@@ -1391,6 +1494,13 @@ MediaDevices.prototype.enumerateDevices = function() {};
  */
 MediaDevices.prototype.getUserMedia = function(constraints) {}
 
+/**
+ * @see https://w3c.github.io/mediacapture-screen-share/#dom-mediadevices-getdisplaymedia
+ * @param {!MediaStreamConstraints=} constraints
+ * @return {!Promise<!MediaStream>}
+ */
+MediaDevices.prototype.getDisplayMedia = function(constraints) {}
+
 /**
  * @see https://w3c.github.io/mediacapture-main/#dom-mediadevices-getsupportedconstraints
  * @return {!MediaTrackSupportedConstraints}
@@ -1487,7 +1597,7 @@ RTCIceCandidate.prototype.sdpMid;
 RTCIceCandidate.prototype.sdpMLineIndex;
 
 /**
- * @typedef {{urls: string}|{urls: !Array<!string>}}
+ * @typedef {{urls: string}|{urls: !Array<string>}}
  * @private
  * @see https://www.w3.org/TR/webrtc/#rtciceserver-dictionary
  * This dictionary type also has an optional key {credential: ?string}.
@@ -1501,7 +1611,7 @@ var RTCIceServerRecord_;
 function RTCIceServerInterface_() {}
 
 /**
- * @type {string|!Array<!string>}
+ * @type {string|!Array<string>}
  */
 RTCIceServerInterface_.prototype.urls;
 
@@ -1587,6 +1697,12 @@ var RTCIceConnectionState;
  */
 var RTCIceGatheringState;
 
+/**
+ * @see https://www.w3.org/TR/webrtc/#rtcpeerconnectionstate-enum
+ * @typedef {string}
+ */
+var RTCPeerConnectionState;
+
 /**
  * @param {string} type
  * @param {!Object} eventInitDict
@@ -1595,8 +1711,7 @@ var RTCIceGatheringState;
 function RTCPeerConnectionIceEvent(type, eventInitDict) {}
 
 /**
- * @type {RTCIceCandidate}
- * @const
+ * @const {RTCIceCandidate}
  */
 RTCPeerConnectionIceEvent.prototype.candidate;
 
@@ -1605,18 +1720,540 @@ RTCPeerConnectionIceEvent.prototype.candidate;
 // modern browsers, breaking compatibility with older versions as they become
 // obsolete.
 /**
+ * @see https://www.w3.org/TR/webrtc/#dom-rtcstats
+ * @interface
+ */
+function RTCStats() {}
+
+/**
+ * @const {?Date|number}
+ */
+RTCStats.prototype.timestamp;
+
+/**
+ * https://www.w3.org/TR/webrtc-stats/#rtcstatstype-str*
+ * @const {string}
+ */
+RTCStats.prototype.type;
+
+/**
+ * @const {string}
+ */
+RTCStats.prototype.id;
+
+/**
+ * @see https://www.w3.org/TR/webrtc-stats/#dom-rtcrtpstreamstats
+ * @interface
+ * @extends {RTCStats}
+ */
+function RTCRtpStreamStats() {}
+
+/** @const {number} */
+RTCRtpStreamStats.prototype.ssrc;
+
+/** @const {string} */
+RTCRtpStreamStats.prototype.kind;
+
+/**
+ * Safari 13 still uses .mediaType instead of .kind.
+ * @const {string}
+ */
+RTCRtpStreamStats.prototype.mediaType;
+
+/** @const {string} */
+RTCRtpStreamStats.prototype.transportId;
+
+/** @const {string} */
+RTCRtpStreamStats.prototype.codecId;
+
+
+/**
+ * @see https://www.w3.org/TR/webrtc-stats/#dom-rtcreceivedrtpstreamstats
+ * @interface
+ * @extends {RTCRtpStreamStats}
+ */
+function RTCReceivedRtpStreamStats() {}
+
+/** @const {number} */
+RTCReceivedRtpStreamStats.prototype.packetsReceived;
+
+/** @const {number} */
+RTCReceivedRtpStreamStats.prototype.packetsLost;
+
+/** @const {number} */
+RTCReceivedRtpStreamStats.prototype.jitter;
+
+/** @const {number} */
+RTCReceivedRtpStreamStats.prototype.packetsDiscarded;
+
+/** @const {number} */
+RTCReceivedRtpStreamStats.prototype.packetsRepaired;
+
+/** @const {number} */
+RTCReceivedRtpStreamStats.prototype.burstPacketsLost;
+
+/** @const {number} */
+RTCReceivedRtpStreamStats.prototype.burstPacketsDiscarded;
+
+/** @const {number} */
+RTCReceivedRtpStreamStats.prototype.burstLossCount;
+
+/** @const {number} */
+RTCReceivedRtpStreamStats.prototype.burstDiscardCount;
+
+/** @const {number} */
+RTCReceivedRtpStreamStats.prototype.burstLossRate;
+
+/** @const {number} */
+RTCReceivedRtpStreamStats.prototype.burstDiscardRate;
+
+/** @const {number} */
+RTCReceivedRtpStreamStats.prototype.gapLossRate;
+
+/** @const {number} */
+RTCReceivedRtpStreamStats.prototype.gapDiscardRate;
+
+
+
+/**
+ * @see https://www.w3.org/TR/webrtc-stats/#dom-rtcinboundrtpstreamstats
  * @interface
+ * @extends {RTCReceivedRtpStreamStats}
+ */
+function RTCInboundRtpStreamStats() {}
+
+/** @const {string} */
+RTCInboundRtpStreamStats.prototype.trackId;
+
+/** @const {string} */
+RTCInboundRtpStreamStats.prototype.receiverId;
+
+/** @const {string} */
+RTCInboundRtpStreamStats.prototype.remoteId;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.framesDecoded;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.keyFramesDecoded;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.frameWidth;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.frameHeight;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.frameBitDepth;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.framesPerSecond;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.qpSum;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.totalDecodeTime;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.totalInterframeDelay;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.totalSquaredInterFrameDelay;
+
+/** @const {boolean} */
+RTCInboundRtpStreamStats.prototype.voiceActivityFlag;
+
+/** @const {?Date|number} */
+RTCInboundRtpStreamStats.prototype.lastPacketReceivedTimestamp;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.averageRtcpInterval;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.headerBytesReceived;
+
+/**
+ * Not available in Safari 13, Firefox 69 (Chrome 81+ only).
+ * @const {number|undefined}
+ */
+RTCInboundRtpStreamStats.prototype.fecPacketsReceived;
+
+/**
+ * Not available in Safari 13, Firefox 69 (Chrome 81+ only).
+ * @const {number|undefined}
+ */
+RTCInboundRtpStreamStats.prototype.fecPacketsDiscarded;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.bytesReceived;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.packetsFailedDecryption;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.packetsDuplicated;
+
+// TODO: record<USVString, unsigned long long> perDscpPacketsReceived;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.nackCount;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.firCount;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.pliCount;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.sliCount;
+
+/** @const {?Date|number} */
+RTCInboundRtpStreamStats.prototype.estimatedPlayoutTimestamp;
+
+/**
+ * Firefox specific value.
+ * @const {number|undefined}
+ */
+RTCInboundRtpStreamStats.prototype.bitrateMean;
+
+/** @const {number|undefined} */
+RTCInboundRtpStreamStats.prototype.jitterBufferDelay;
+
+/** @const {number|undefined} */
+RTCInboundRtpStreamStats.prototype.jitterBufferEmittedCount;
+
+/**
+ * Experimental chrome stats under this origin trial:
+ * https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/hE2B1iItPDk
+ * @const {number|undefined}
+ */
+RTCInboundRtpStreamStats.prototype.jitterBufferFlushes;
+
+/** @const {number|undefined} */
+RTCInboundRtpStreamStats.prototype.totalSamplesReceived;
+
+/** @const {number|undefined} */
+RTCInboundRtpStreamStats.prototype.samplesDecodedWithSilk;
+
+/** @const {number|undefined} */
+RTCInboundRtpStreamStats.prototype.samplesDecodedWithCelt;
+
+/** @const {number|undefined} */
+RTCInboundRtpStreamStats.prototype.concealedSamples;
+
+/**
+ * Not available in Safari 13.
+ * @const {number|undefined}
+ */
+RTCInboundRtpStreamStats.prototype.silentConcealedSamples;
+
+/**
+ * Not available in Safari 13.
+ * @const {number|undefined}
+ */
+RTCInboundRtpStreamStats.prototype.concealmentEvents;
+
+/**
+ * Not available in Safari 13.
+ * @const {number|undefined}
+ */
+RTCInboundRtpStreamStats.prototype.insertedSamplesForDeceleration
+
+/**
+ * Not available in Safari 13.
+ * @const {number|undefined}
+ */
+RTCInboundRtpStreamStats.prototype.removedSamplesForAcceleration;
+
+/**
+ * Experimental chrome stats under this origin trial:
+ * https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/hE2B1iItPDk
+ * @const {number|undefined}
+ */
+RTCInboundRtpStreamStats.prototype.delayedPacketOutageSamples;
+
+/**
+ * Safari still reprorting it as inbound-rtp, it supposed to be in remote part.
+ * @const {number|undefined}
+ */
+RTCInboundRtpStreamStats.prototype.fractionLost;
+
+/** @const {number} */
+RTCInboundRtpStreamStats.prototype.audioLevel;
+
+/** @const {number|undefined} */
+RTCInboundRtpStreamStats.prototype.totalAudioEnergy;
+
+/** @const {number|undefined} */
+RTCInboundRtpStreamStats.prototype.totalSamplesDuration;
+
+/** @const {number|undefined} */
+RTCInboundRtpStreamStats.prototype.framesReceived;
+
+/** @const {string|undefined} */
+RTCInboundRtpStreamStats.prototype.decoderImplementation;
+
+
+
+/**
+ * @see https://www.w3.org/TR/webrtc-stats/#dom-rtcremoteinboundrtpstreamstats
+ * @interface
+ * @extends {RTCReceivedRtpStreamStats}
+ */
+function RTCRemoteInboundRtpStreamStats() {}
+
+/** @const {string} */
+RTCRemoteInboundRtpStreamStats.prototype.localId;
+
+/** @const {number} */
+RTCRemoteInboundRtpStreamStats.prototype.roundTripTime;
+
+/** @const {number} */
+RTCRemoteInboundRtpStreamStats.prototype.fractionLost;
+
+
+/**
+ * @see https://www.w3.org/TR/webrtc-stats/#dom-rtcsentrtpstreamstats
+ * @interface
+ * @extends {RTCRtpStreamStats}
+ */
+function RTCSentRtpStreamStats() {}
+
+/** @const {number} */
+RTCSentRtpStreamStats.prototype.packetsSent;
+
+/** @const {number} */
+RTCSentRtpStreamStats.prototype.packetsDiscardedOnSend;
+
+/** @const {number} */
+RTCSentRtpStreamStats.prototype.fecPacketsSent;
+
+/** @const {number} */
+RTCSentRtpStreamStats.prototype.bytesSent;
+
+/** @const {number} */
+RTCSentRtpStreamStats.prototype.bytesDiscardedOnSend;
+
+
+/**
+/**
+ * @see https://www.w3.org/TR/webrtc-stats/#dom-rtcoutboundrtpstreamstats
+ * @interface
+ * @extends {RTCSentRtpStreamStats}
+ */
+function RTCOutboundRtpStreamStats() {}
+
+/** @const {string} */
+RTCOutboundRtpStreamStats.prototype.trackId;
+
+/** @const {string} */
+RTCOutboundRtpStreamStats.prototype.senderId;
+
+/** @const {string} */
+RTCOutboundRtpStreamStats.prototype.remoteId;
+
+/** @const {number} */
+RTCOutboundRtpStreamStats.prototype.lastPacketSentTimestamp;
+
+/** @const {number} */
+RTCOutboundRtpStreamStats.prototype.targetBitrate;
+
+/** @const {number} */
+RTCOutboundRtpStreamStats.prototype.framesEncoded;
+
+/** @const {number} */
+RTCOutboundRtpStreamStats.prototype.totalEncodeTime;
+
+/** @const {number} */
+RTCOutboundRtpStreamStats.prototype.averageRTCPInterval;
+
+/** @const {number|undefined} */
+RTCOutboundRtpStreamStats.prototype.qualityLimitationResolutionChanges;
+
+/** @const {string|undefined} */
+RTCOutboundRtpStreamStats.prototype.qualityLimitationReason;
+
+/** @const {string} */
+RTCOutboundRtpStreamStats.prototype.mediaSourceId;
+
+/** @const {number} */
+RTCOutboundRtpStreamStats.prototype.frameWidth;
+
+/** @const {number} */
+RTCOutboundRtpStreamStats.prototype.frameHeight;
+
+/** @const {number} */
+RTCOutboundRtpStreamStats.prototype.qpSum;
+
+/**
+ * Firefox specific value.
+ * @const {number|undefined}
+ */
+RTCOutboundRtpStreamStats.prototype.bitrateMean;
+
+/** @const {number} */
+RTCOutboundRtpStreamStats.prototype.nackCount;
+
+/** @const {number} */
+RTCOutboundRtpStreamStats.prototype.firCount;
+
+/** @const {number} */
+RTCOutboundRtpStreamStats.prototype.pliCount;
+
+/** @const {number} */
+RTCOutboundRtpStreamStats.prototype.sliCount;
+
+/** @const {string|undefined} */
+RTCOutboundRtpStreamStats.prototype.encoderImplementation;
+
+
+/**
+ * @see https://www.w3.org/TR/webrtc-stats/#dom-rtcremoteoutboundrtpstreamstats
+ * @interface
+ * @extends {RTCSentRtpStreamStats}
+ */
+function RTCRemoteOutboundRtpStreamStats() {}
+
+/** @const {string} */
+RTCRemoteOutboundRtpStreamStats.prototype.localId;
+
+/** @const {?Date|number} */
+RTCRemoteOutboundRtpStreamStats.prototype.remoteTimestamp;
+
+
+/**
+ * @see https://www.w3.org/TR/webrtc-stats/#transportstats-dict*
+ * @interface
+ * @extends {RTCStats}
+ */
+function RTCTransportStats() {}
+
+/** @type {number} */
+RTCTransportStats.prototype.packetsSent;
+
+/** @type {number} */
+RTCTransportStats.prototype.packetsReceived;
+
+/** @type {number} */
+RTCTransportStats.prototype.bytesSent;
+
+/** @type {number} */
+RTCTransportStats.prototype.bytesReceived;
+
+/** @type {string} */
+RTCTransportStats.prototype.rtcpTransportStatsId;
+
+/**
+ * @type {string}
+ * Set of possible string values: 'unknown', 'controlling', 'controlled'.
+ */
+RTCTransportStats.prototype.iceRole;
+
+/**
+ * @type {string}
+ * Set of possible string values: 'new', 'connecting', 'connected',
+ * 'closed', 'failed'.
+ */
+RTCTransportStats.prototype.dtlsState;
+
+/** @type {string} */
+RTCTransportStats.prototype.selectedCandidatePairId;
+
+/** @type {string} */
+RTCTransportStats.prototype.localCertificateId;
+
+/** @type {string} */
+RTCTransportStats.prototype.remoteCertificateId;
+
+/** @type {string} */
+RTCTransportStats.prototype.tlsVersion;
+
+/** @type {string} */
+RTCTransportStats.prototype.dtlsCipher;
+
+/** @type {string} */
+RTCTransportStats.prototype.srtpCipher;
+
+/** @type {string} */
+RTCTransportStats.prototype.tlsGroup;
+
+/** @type {number} */
+RTCTransportStats.prototype.selectedCandidatePairChanges;
+
+
+/**
+ * @see https://w3c.github.io/webrtc-stats/#dom-rtcmediasourcestats
+ * @interface
+ * @extends {RTCStats}
+ */
+function RTCMediaSourceStats() {}
+
+/** @const {string} */
+RTCMediaSourceStats.prototype.trackIdentifier;
+
+/** @const {string} */
+RTCMediaSourceStats.prototype.kind;
+
+/**
+ * @see https://w3c.github.io/webrtc-stats/#dom-rtcvideosourcestats
+ * @interface
+ * @extends {RTCMediaSourceStats}
+ */
+function RTCVideoSourceStats() {}
+
+/** @const {number} */
+RTCVideoSourceStats.prototype.width;
+
+/** @const {number} */
+RTCVideoSourceStats.prototype.height;
+
+/** @const {number} */
+RTCVideoSourceStats.prototype.bitDepth;
+
+/** @const {number} */
+RTCVideoSourceStats.prototype.frames;
+
+/** @const {number} */
+RTCVideoSourceStats.prototype.framesPerSecond;
+
+/**
+ * @see https://w3c.github.io/webrtc-stats/#dom-rtcaudiosourcestats
+ * @interface
+ * @extends {RTCMediaSourceStats}
+ */
+function RTCAudioSourceStats() {}
+
+/** @const {number} */
+RTCAudioSourceStats.prototype.audioLevel;
+
+/** @const {number} */
+RTCAudioSourceStats.prototype.totalAudioEnergy;
+
+/** @const {number} */
+RTCAudioSourceStats.prototype.totalSamplesDuration;
+
+/** @const {number} */
+RTCAudioSourceStats.prototype.echoReturnLoss;
+
+/** @const {number} */
+RTCAudioSourceStats.prototype.echoReturnLossEnhancement;
+
+
+/**
+ * @interface
+ * @extends {Iterable<!Array<string|!RTCStats>>}
+ * @see https://w3c.github.io/webrtc-pc/#rtcstatsreport-object
  */
 function RTCStatsReport() {}
 
 /**
- * @type {Date}
- * @const
+ * @const {?Date|number}
  */
 RTCStatsReport.prototype.timestamp;
 
 /**
- * @return {!Array<!string>}
+ * @return {!Array<string>}
  */
 RTCStatsReport.prototype.names = function() {};
 
@@ -1628,27 +2265,23 @@ RTCStatsReport.prototype.stat = function(name) {};
 
 /**
  * @deprecated
- * @type {RTCStatsReport}
- * @const
+ * @const {RTCStatsReport}
  */
 RTCStatsReport.prototype.local;
 
 /**
  * @deprecated
- * @type {RTCStatsReport}
- * @const
+ * @const {RTCStatsReport}
  */
 RTCStatsReport.prototype.remote;
 
 /**
- * @type {string}
- * @const
+ * @const {string}
  */
 RTCStatsReport.prototype.type;
 
 /**
- * @type {string}
- * @const
+ * @const {string}
  */
 RTCStatsReport.prototype.id;
 
@@ -1657,27 +2290,52 @@ RTCStatsReport.prototype.id;
 // Mozilla.
 // See https://www.w3.org/TR/webrtc/#rtcstatsreport-object for definition.
 /**
- * @param {function(this:SCOPE, Object, string, MAP)} callback
+ * @param {function(this:SCOPE, !RTCStats, string, MAP)} callback
  * @param {SCOPE=} opt_thisObj The value of "this" inside callback function.
  * @this {MAP}
  * @template MAP,SCOPE
- * @readonly
  */
 RTCStatsReport.prototype.forEach = function(callback, opt_thisObj) {};
 
 /**
  * @param {string} key
- * @return {Object}
- * @readonly
+ * @return {!IteratorIterable<!Array<string|!RTCStats>>}
+ */
+RTCStatsReport.prototype.entries = function(key) {};
+
+/**
+ * @param {string} key
+ * @return {!RTCStats}
  */
 RTCStatsReport.prototype.get = function(key) {};
 
 /**
  * @return {!IteratorIterable<string>}
- * @readonly
  */
 RTCStatsReport.prototype.keys = function() {};
 
+/**
+ * @return {!IteratorIterable<!RTCStats>}
+ */
+RTCStatsReport.prototype.values = function() {};
+
+/**
+ * @param {string} key
+ * @return {boolean}
+ */
+RTCStatsReport.prototype.has = function(key) {};
+
+/**
+ * @const {number}
+ */
+RTCStatsReport.prototype.size;
+
+/**
+ * @return {!Iterator<!Array<string|!RTCStats>>}
+ */
+RTCStatsReport.prototype[Symbol.iterator] = function() {};
+
+
 /**
  * TODO(bemasc): Remove this type once it is no longer in use.  It has already
  * been removed from the specification.
@@ -1768,18 +2426,17 @@ var MediaConstraints;
 /**
  * @interface
  * @extends {EventTarget}
+ * @see https://w3c.github.io/webrtc-pc/#dom-rtcdatachannel
  */
 function RTCDataChannel() {}
 
 /**
- * @type {string}
- * @const
+ * @const {string}
  */
 RTCDataChannel.prototype.label;
 
 /**
- * @type {boolean}
- * @const
+ * @const {boolean}
  */
 RTCDataChannel.prototype.reliable;
 
@@ -1797,6 +2454,11 @@ RTCDataChannel.prototype.readyState;
  */
 RTCDataChannel.prototype.bufferedAmount;
 
+/**
+ * @type {number}
+ */
+RTCDataChannel.prototype.bufferedAmountLowThreshold;
+
 /**
  * @type {?function(!Event)}
  */
@@ -1819,6 +2481,11 @@ RTCDataChannel.prototype.close = function() {};
  */
 RTCDataChannel.prototype.onmessage;
 
+/**
+ * @type {?function(!Event)}
+ */
+RTCDataChannel.prototype.onbufferedamountlow;
+
 /**
  * @type {string}
  */
@@ -1860,14 +2527,15 @@ function RTCDataChannelInitInterface_() {}
 RTCDataChannelInitInterface_.prototype.reliable;
 
 /**
- * @typedef {Object}
- * @property {boolean=} [ordered=true]
- * @property {number=} maxPacketLifeTime
- * @property {number=} maxRetransmits
- * @property {string=} [protocol=""]
- * @property {boolean=} [negotiated=false]
- * @property {number=} id
- * @property {string=} [priority='low']
+ * @typedef {{
+ *   ordered: (boolean|undefined),
+ *   maxPacketLifeTime: (number|undefined),
+ *   maxRetransmits: (number|undefined),
+ *   protocol: (string|undefined),
+ *   negotiated: (boolean|undefined),
+ *   id: (number|undefined),
+ *   priority: (string|undefined),
+ * }}
  * see https://www.w3.org/TR/webrtc/#dom-rtcdatachannelinit for documentation
  * Type inconsistencies due to Closure limitations:
  * maxPacketLifeTime should be UnsignedShort
@@ -1895,6 +2563,7 @@ var RTCCertificate;
  * @param {!MediaConstraints=} constraints
  * @constructor
  * @implements {EventTarget}
+ * @see https://www.w3.org/TR/webrtc/#interface-definition
  */
 function RTCPeerConnection(configuration, constraints) {}
 
@@ -1950,7 +2619,7 @@ RTCPeerConnection.prototype.createAnswer =
     function(successCallbackOrConstraints, errorCallback, constraints) {};
 
 /**
- * @param {!RTCSessionDescription} description
+ * @param {!RTCSessionDescription=} description
  * @param {!RTCVoidCallback=} successCallback
  * @param {!RTCPeerConnectionErrorCallback=} errorCallback
  * @return {!Promise<!RTCSessionDescription>}
@@ -1996,7 +2665,7 @@ RTCPeerConnection.prototype.updateIce = function(configuration, constraints) {};
  * Void in Chrome for now, a promise that you can then/catch in Firefox.
  * @param {!RTCIceCandidate} candidate
  * @param {!RTCVoidCallback=} successCallback
- * @param {!function(DOMException)=} errorCallback
+ * @param {function(DOMException)=} errorCallback
  * @return {!Promise|undefined}
  */
 RTCPeerConnection.prototype.addIceCandidate = function(candidate, successCallback, errorCallback) {};
@@ -2013,6 +2682,12 @@ RTCPeerConnection.prototype.iceGatheringState;
  */
 RTCPeerConnection.prototype.iceConnectionState;
 
+/**
+ * @type {!RTCPeerConnectionState}
+ * Read only.
+ */
+RTCPeerConnection.prototype.connectionState;
+
 /**
  * @return {!Array<!MediaStream>}
  */
@@ -2123,6 +2798,11 @@ RTCPeerConnection.prototype.onnegotiationneeded;
  */
 RTCPeerConnection.prototype.onicecandidate;
 
+/**
+ * @type {?function(!Event)}
+ */
+RTCPeerConnection.prototype.onicegatheringstatechange;
+
 /**
  * @type {?function(!Event)}
  */
@@ -2154,99 +2834,51 @@ RTCPeerConnection.prototype.oniceconnectionstatechange;
 RTCPeerConnection.prototype.ondatachannel;
 
 /**
- * @const
+ * @type {?function(!Event)}
  */
-var webkitRTCPeerConnection = RTCPeerConnection;
+RTCPeerConnection.prototype.onconnectionstatechange;
 
 /**
- * @const
+ * @typedef {string}
+ * @see https://www.w3.org/TR/webrtc/#dom-rtcerrordetailtype
+ * Possible values: 'data-channel-failure', 'dtls-failure',
+ *   'fingerprint-failure', 'sctp-failure', 'sdp-syntax-error',
+ *   'hardware-encoder-not-available', 'hardware-encoder-error'
  */
-var mozRTCPeerConnection = RTCPeerConnection;
+var RTCErrorDetailType;
 
 /**
+ * @see https://www.w3.org/TR/webrtc/#rtcerror-interface
  * @interface
- * @param {RTCIceGatherer} iceGatherer
- * @see https://www.w3.org/TR/webrtc/#idl-def-rtcicetransport
  */
-function RTCIceTransport(iceGatherer) {}
+function RTCError() {}
 
-/**
- * @type {!RTCIceGatheringState}
- * @const
- */
-RTCIceTransport.prototype.gatheringState;
+/** @const {!RTCErrorDetailType} */
+RTCError.prototype.errorDetail;
 
-/**
- * @return {RTCIceCandidate[]}
- */
-RTCIceTransport.prototype.getLocalCandidates = function(){};
+/** @const {number|undefined} */
+RTCError.prototype.sdpLineNumber;
 
-/**
- * @return {RTCIceCandidate[]}
- */
-RTCIceTransport.prototype.getRemoteCandidates = function(){};
+/** @const {number|undefined} */
+RTCError.prototype.httpRequestStatusCode;
 
-/**
- * @return {RTCIceCandidatePair}
- */
-RTCIceTransport.prototype.getSelectedCandidatePair = function(){};
+/** @const {number|undefined} */
+RTCError.prototype.sctpCauseCode;
 
-/**
- * @return {RTCIceParameters}
- */
-RTCIceTransport.prototype.getLocalParameters = function(){};
-
-/**
- * @return {RTCIceParameters}
- */
-RTCIceTransport.prototype.getRemoteParameters = function(){};
+/** @const {number|undefined} */
+RTCError.prototype.receivedAlert;
 
-/**
- * @param {!Event} e
- * @return {undefined}
- */
-RTCIceTransport.prototype.onstatechange = function(e){};
-
-/**
- * @param {!Event} e
- * @return {undefined}
- */
-RTCIceTransport.prototype.ongatheringstatechange = function(e){};
-
-/**
- * @param {!Event} e
- * @return {undefined}
- */
-RTCIceTransport.prototype.onselectedcandidatepairchange = function(e){};
-
-
-/**
- * @constructor
- * @param {!RTCIceGatherOptions} options
- * @see https://msdn.microsoft.com/en-us/library/mt433107(v=vs.85).aspx
- */
-function RTCIceGatherer(options) {}
+/** @const {number|undefined} */
+RTCError.prototype.sentAlert;
 
 /**
+ * @see https://www.w3.org/TR/webrtc/#rtcerrorevent-interface
  * @interface
- * @param {RTCIceTransport} iceTransport
- * @see https://www.w3.org/TR/webrtc/#idl-def-rtcdtlstransport
- */
-function RTCDtlsTransport(iceTransport) {}
-
-/**
- * @type {RTCIceTransport}
- * @const
  */
-RTCDtlsTransport.prototype.transport;
+function RTCErrorEvent() {}
 
-/**
- * @return {ArrayBuffer[]}
- */
-RTCDtlsTransport.prototype.getRemoteCertificates = function() {};
+/** @const {!RTCError} */
+RTCErrorEvent.prototype.error;
 
-/**
- * @param {!Event} e
- * @return {undefined}
- */
-RTCDtlsTransport.prototype.onstatechange = function(e){};
+/** @const {string} */
+RTCErrorEvent.prototype.message;
diff --git a/javascript/externs/web/w3c_serviceworker.js b/javascript/externs/web/w3c_serviceworker.js
index f88ece161244..00dbf05cbce6 100644
--- a/javascript/externs/web/w3c_serviceworker.js
+++ b/javascript/externs/web/w3c_serviceworker.js
@@ -41,7 +41,55 @@ ServiceWorker.prototype.onstatechange;
  * 'activated', 'redundant'.
  *  @typedef {string}
  */
-var ServiceWorkerState ;
+var ServiceWorkerState;
+
+/**
+ * @see https://w3c.github.io/ServiceWorker/#navigationpreloadmanager
+ * @constructor
+ */
+function NavigationPreloadManager() {}
+
+/** @return {!Promise<void>} */
+NavigationPreloadManager.prototype.enable = function() {};
+
+/** @return {!Promise<void>} */
+NavigationPreloadManager.prototype.disable = function() {};
+
+/**
+ * @param {string=} value
+ * @return {!Promise<void>}
+ */
+NavigationPreloadManager.prototype.setHeaderValue = function(value) {};
+
+/** @return {!Promise<NavigationPreloadState>} */
+NavigationPreloadManager.prototype.getState = function() {};
+
+/**
+ *  @typedef {{
+ *   enabled: (boolean|undefined),
+ *   headerValue: (string|undefined)
+ * }}
+ */
+var NavigationPreloadState;
+
+/** @record */
+function PushSubscriptionOptions() {}
+
+/** @type {ArrayBuffer|undefined} */
+PushSubscriptionOptions.prototype.applicationServerKey;
+
+/** @type {boolean|undefined} */
+PushSubscriptionOptions.prototype.userVisibleOnly;
+
+/** @record */
+function PushSubscriptionOptionsInit() {}
+
+/** @type {BufferSource|string|undefined} */
+PushSubscriptionOptionsInit.prototype.applicationServerKey;
+
+/** @type {boolean|undefined} */
+PushSubscriptionOptionsInit.prototype.userVisibleOnly;
+
 
 /**
  * @see https://w3c.github.io/push-api/
@@ -59,6 +107,9 @@ PushSubscription.prototype.endpoint;
  */
 PushSubscription.prototype.subscriptionId;
 
+/** @type {!PushSubscriptionOptions} */
+PushSubscription.prototype.options;
+
 /** @return {!Promise<boolean>} */
 PushSubscription.prototype.unsubscribe = function() {};
 
@@ -78,8 +129,8 @@ PushSubscription.prototype.unsubscribe = function() {};
 function PushManager() {}
 
 /**
- * @param {PushSubscriptionOptions=} opt_options
- * @return {!Promise<PushSubscription>}
+ * @param {PushSubscriptionOptionsInit=} opt_options
+ * @return {!Promise<!PushSubscription>}
  */
 PushManager.prototype.subscribe = function(opt_options) {};
 
@@ -92,10 +143,34 @@ PushManager.prototype.getSubscription = function() {};
 // PushManager.prototype.hasPermission = function() {};
 
 /**
- * @typedef {{userVisibleOnly: (boolean|undefined)}}
- * @see https://w3c.github.io/push-api/#idl-def-PushSubscriptionOptions
+ * @see https://wicg.github.io/BackgroundSync/spec/#sync-manager-interface
+ * @constructor
+ */
+function SyncManager() {}
+
+/**
+ * @param {string} tag
+ * @return {!Promise<void>}
+ */
+SyncManager.prototype.register = function(tag) {}
+
+/**
+ * @return {!Promise<Array<string>>}
  */
-var PushSubscriptionOptions;
+SyncManager.prototype.getTags = function() {}
+
+/**
+ * @see https://wicg.github.io/BackgroundSync/spec/#sync-event
+ * @constructor
+ * @extends{ExtendableEvent}
+ */
+function SyncEvent() {}
+
+/** @type {string} */
+SyncEvent.prototype.tag;
+
+/** @type {boolean} */
+SyncEvent.prototype.lastChance;
 
 /**
  * @see http://www.w3.org/TR/push-api/#idl-def-PushMessageData
@@ -145,6 +220,9 @@ ServiceWorkerRegistration.prototype.waiting;
 /** @type {ServiceWorker} */
 ServiceWorkerRegistration.prototype.active;
 
+/** @type {NavigationPreloadManager} */
+ServiceWorkerRegistration.prototype.navigationPreload;
+
 /** @type {string} */
 ServiceWorkerRegistration.prototype.scope;
 
@@ -179,6 +257,12 @@ ServiceWorkerRegistration.prototype.showNotification =
  */
 ServiceWorkerRegistration.prototype.getNotifications = function(opt_filter) {};
 
+/**
+ * @see https://wicg.github.io/BackgroundSync/spec/#service-worker-registration-extensions
+ * @type {!SyncManager}
+ */
+ServiceWorkerRegistration.prototype.sync;
+
 /**
  * @see http://www.w3.org/TR/service-workers/#service-worker-container-interface
  * @interface
@@ -193,7 +277,7 @@ ServiceWorkerContainer.prototype.controller;
 ServiceWorkerContainer.prototype.ready;
 
 /**
- * @param {string} scriptURL
+ * @param {!TrustedScriptURL|string} scriptURL
  * @param {RegistrationOptions=} opt_options
  * @return {!Promise<!ServiceWorkerRegistration>}
  */
@@ -210,14 +294,17 @@ ServiceWorkerContainer.prototype.getRegistration = function(opt_documentURL) {};
  */
 ServiceWorkerContainer.prototype.getRegistrations = function() {};
 
-/** @type {?function(!Event)} */
+/** @type {?function(!Event): void} */
 ServiceWorkerContainer.prototype.oncontrollerchange;
 
-/** @type {?function(!ErrorEvent)} */
+/** @type {?function(!ExtendableMessageEvent): void} */
+ServiceWorkerContainer.prototype.onmessage;
+
+/** @type {?function(!ErrorEvent): void} */
 ServiceWorkerContainer.prototype.onerror;
 
 /**
- * @typedef {{scope: (string|undefined), useCache: (boolean|undefined)}}
+ * @typedef {{scope: (string|undefined), useCache: (boolean|undefined), updateViaCache: (string|undefined)}}
  */
 var RegistrationOptions;
 
@@ -276,8 +363,19 @@ ServiceWorkerGlobalScope.prototype.onevicted;
 /** @type {?function(!MessageEvent)} */
 ServiceWorkerGlobalScope.prototype.onmessage;
 
-/** @type {!IDBFactory|undefined} */
-ServiceWorkerGlobalScope.prototype.indexedDB;
+/**
+ * While not strictly correct, this should be effectively correct. Notification
+ * is the Notification constructor but calling it from the Service Worker throws
+ * (https://notifications.spec.whatwg.org/#constructors) so its only use is as
+ * an object holding some static properties (note that requestPermission is only
+ * exposed to window context - https://notifications.spec.whatwg.org/#api).
+ *
+ * @type {{
+ *   permission: string,
+ *   maxActions: number,
+ * }}
+ */
+ServiceWorkerGlobalScope.prototype.Notification;
 
 /**
  * @see http://www.w3.org/TR/service-workers/#service-worker-client-interface
@@ -300,6 +398,9 @@ ServiceWorkerClient.prototype.visibilityState;
 /** @type {string} */
 ServiceWorkerClient.prototype.url;
 
+/** @type {string} */
+ServiceWorkerClient.prototype.id;
+
 /**
  * // TODO(mtragut): Possibly replace the type with enum ContextFrameType once
  * the enum is defined.
@@ -317,6 +418,12 @@ ServiceWorkerClient.prototype.postMessage = function(message, opt_transfer) {};
 /** @return {!Promise} */
 ServiceWorkerClient.prototype.focus = function() {};
 
+/**
+ * @param {string} url
+ * @return {!Promise<!ServiceWorkerClient>}
+ */
+ServiceWorkerClient.prototype.navigate = function(url) {};
+
 /**
  * @see http://www.w3.org/TR/service-workers/#service-worker-clients-interface
  * @interface
@@ -349,6 +456,12 @@ ServiceWorkerClients.prototype.claim = function() {};
  */
 ServiceWorkerClients.prototype.openWindow = function(url) {};
 
+/**
+ * @param {string} id
+ * @return {!Promise<!ServiceWorkerClient|undefined>}
+ */
+ServiceWorkerClients.prototype.get = function(id) {};
+
 /** @typedef {{includeUncontrolled: (boolean|undefined)}} */
 var ServiceWorkerClientQueryOptions;
 
@@ -506,21 +619,35 @@ var InstallEventInit;
  * @constructor
  * @param {string} type
  * @param {FetchEventInit=} opt_eventInitDict
- * @extends {Event}
+ * @extends {ExtendableEvent}
  */
 function FetchEvent(type, opt_eventInitDict) {}
 
 /** @type {!Request} */
 FetchEvent.prototype.request;
 
-/** @type {!ServiceWorkerClient} */
+/**
+ * @type {!Promise<Response>}
+ */
+FetchEvent.prototype.preloadResponse;
+
+/**
+ * @type {!ServiceWorkerClient}
+ * @deprecated
+ */
 FetchEvent.prototype.client;
 
-/** @type {!boolean} */
+/** @type {?string} */
+FetchEvent.prototype.clientId;
+
+/** @type {boolean} */
 FetchEvent.prototype.isReload;
 
+/** @type {?string} */
+FetchEvent.prototype.resultingClientId;
+
 /**
- * @param {(Response|Promise<Response>)} r
+ * @param {(Response|IThenable<Response>)} r
  * @return {undefined}
  */
 FetchEvent.prototype.respondWith = function(r) {};
@@ -541,8 +668,59 @@ FetchEvent.prototype.default = function() {};
  *   bubbles: (boolean|undefined),
  *   cancelable: (boolean|undefined),
  *   request: (!Request|undefined),
+ *   preloadResponse: (!Promise<Response>),
  *   client: (!ServiceWorkerClient|undefined),
- *   isReload: (!boolean|undefined)
+ *   isReload: (boolean|undefined)
  * }}
  */
 var FetchEventInit;
+
+
+/**
+ * @see https://www.w3.org/TR/service-workers/#extendablemessage-event-interface
+ * @param {string} type
+ * @param {!ExtendableMessageEventInit<T>=} opt_eventInitDict
+ * @constructor
+ * @extends {ExtendableEvent}
+ * @template T
+ */
+function ExtendableMessageEvent(type, opt_eventInitDict) {};
+
+/** @type {T} */
+ExtendableMessageEvent.prototype.data;
+
+/** @type {string} */
+ExtendableMessageEvent.prototype.origin;
+
+/** @type {string} */
+ExtendableMessageEvent.prototype.lastEventId;
+
+/** @type {?ServiceWorkerClient|?ServiceWorker|?MessagePort} */
+ExtendableMessageEvent.prototype.source;
+
+/** @type {?Array<!MessagePort>} */
+ExtendableMessageEvent.prototype.ports;
+
+
+/**
+ * @see https://www.w3.org/TR/service-workers/#extendablemessage-event-init-dictionary
+ * @record
+ * @extends {ExtendableEventInit}
+ * @template T
+ */
+function ExtendableMessageEventInit() {};
+
+/** @type {T} */
+ExtendableMessageEventInit.prototype.data;
+
+/** @type {string|undefined} */
+ExtendableMessageEventInit.prototype.origin;
+
+/** @type {string|undefined} */
+ExtendableMessageEventInit.prototype.lastEventId;
+
+/** @type {!ServiceWorkerClient|!ServiceWorker|!MessagePort|undefined} */
+ExtendableMessageEventInit.prototype.source;
+
+/** @type {!Array<!MessagePort>|undefined} */
+ExtendableMessageEventInit.prototype.ports;
diff --git a/javascript/externs/web/w3c_webcrypto.js b/javascript/externs/web/w3c_webcrypto.js
index ddd16ab399f0..670aa408a218 100644
--- a/javascript/externs/web/w3c_webcrypto.js
+++ b/javascript/externs/web/w3c_webcrypto.js
@@ -47,6 +47,19 @@ webCrypto.Algorithm;
  */
 webCrypto.AlgorithmIdentifier;
 
+/**
+ * @typedef {webCrypto.AlgorithmIdentifier}
+ * @see http://www.w3.org/TR/WebCryptoAPI/#dfn-HashAlgorithmIdentifier
+ */
+webCrypto.HashAlgorithmIdentifier;
+
+
+/**
+ * @typedef {Uint8Array}
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-BigInteger
+ */
+webCrypto.BigInteger;
+
 
 /**
  * @constructor
@@ -85,6 +98,25 @@ webCrypto.CryptoKey.prototype.algorithm;
 webCrypto.CryptoKey.prototype.usages;
 
 
+/**
+ * @constructor
+ * @see https://www.w3.org/TR/WebCryptoAPI/#keypair
+ */
+webCrypto.CryptoKeyPair = function() {};
+
+
+/**
+ * @type {!webCrypto.CryptoKey}
+ */
+webCrypto.CryptoKeyPair.prototype.publicKey;
+
+
+/**
+ * @type {!webCrypto.CryptoKey}
+ */
+webCrypto.CryptoKeyPair.prototype.privateKey;
+
+
 /**
  * @typedef {?{
  *   name: string
@@ -248,6 +280,337 @@ webCrypto.RsaOtherPrimesInfo.prototype.d;
 webCrypto.RsaOtherPrimesInfo.prototype.t;
 
 
+/**
+ * @record
+ * @extends webCrypto.Algorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-RsaKeyGenParams
+ */
+webCrypto.RsaKeyGenParams;
+/**
+ * @type {number}
+ */
+webCrypto.RsaKeyGenParams.prototype.modulusLength;
+/**
+ * @type {webCrypto.BigInteger}
+ */
+webCrypto.RsaKeyGenParams.prototype.publicExponent;
+
+
+/**
+ * @record
+ * @extends webCrypto.RsaKeyGenParams
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-RsaHashedKeyGenParams
+ */
+webCrypto.RsaHashedKeyGenParams;
+/**
+ * @type {webCrypto.HashAlgorithmIdentifier}
+ */
+webCrypto.RsaHashedKeyGenParams.prototype.hash;
+
+
+/**
+ * @record
+ * @extends webCrypto.KeyAlgorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-RsaKeyAlgorithm
+ */
+webCrypto.RsaKeyAlgorithm;
+/**
+ * @type {number}
+ */
+webCrypto.RsaKeyAlgorithm.prototype.modulusLength;
+/**
+ * @type {webCrypto.BigInteger}
+ */
+webCrypto.RsaKeyAlgorithm.prototype.publicExponent;
+
+
+/**
+ * @record
+ * @extends webCrypto.RsaKeyAlgorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-RsaHashedKeyAlgorithm
+ */
+webCrypto.RsaHashedKeyAlgorithm;
+/**
+ * @type {webCrypto.KeyAlgorithm}
+ */
+webCrypto.RsaHashedKeyAlgorithm.prototype.hash;
+
+
+/**
+ * @record
+ * @extends webCrypto.Algorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-RsaHashedImportParams
+ */
+webCrypto.RsaHashedImportParams;
+/**
+ * @type {webCrypto.HashAlgorithmIdentifier}
+ */
+webCrypto.RsaHashedImportParams.prototype.hash;
+
+
+/**
+ * @record
+ * @extends webCrypto.Algorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-RsaPssParams
+ */
+webCrypto.RsaPssParams;
+/**
+ * @type {number}
+ */
+webCrypto.RsaPssParams.prototype.saltLength;
+
+
+/**
+ * @record
+ * @extends webCrypto.Algorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-RsaOaepParams
+ */
+webCrypto.RsaOaepParams;
+/**
+ * @type {!BufferSource}
+ */
+webCrypto.RsaOaepParams.prototype.label;
+
+
+/**
+ * @record
+ * @extends webCrypto.Algorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-EcdsaParams
+ */
+webCrypto.EcdsaParams;
+/**
+ * @type {!webCrypto.HashAlgorithmIdentifier}
+ */
+webCrypto.EcdsaParams.prototype.hash;
+
+
+/**
+ * @typedef {string}
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-NamedCurve
+ */
+webCrypto.NamedCurve;
+
+
+/**
+ * @record
+ * @extends webCrypto.Algorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-EcKeyGenParams
+ */
+webCrypto.EcKeyGenParams;
+/**
+ * @type {!webCrypto.NamedCurve}
+ */
+webCrypto.EcKeyGenParams.prototype.namedCurve;
+
+
+/**
+ * @record
+ * @extends webCrypto.KeyAlgorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-EcKeyAlgorithm
+ */
+webCrypto.EcKeyAlgorithm;
+/**
+ * @type {!webCrypto.NamedCurve}
+ */
+webCrypto.EcKeyAlgorithm.prototype.namedCurve;
+
+
+/**
+ * @record
+ * @extends webCrypto.Algorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-EcKeyImportParams
+ */
+webCrypto.EcKeyImportParams;
+/**
+ * @type {!webCrypto.NamedCurve}
+ */
+webCrypto.EcKeyImportParams.prototype.namedCurve;
+
+
+/**
+ * @record
+ * @extends webCrypto.Algorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-EcKeyDeriveParams
+ */
+webCrypto.EcKeyDeriveParams;
+/**
+ * @type {!webCrypto.CryptoKey}
+ */
+webCrypto.EcKeyDeriveParams.prototype.public;
+
+
+/**
+ * @record
+ * @extends webCrypto.Algorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-AesCtrParams
+ */
+webCrypto.AesCtrParams;
+/**
+ * @type {!BufferSource}
+ */
+webCrypto.AesCtrParams.prototype.counter;
+/**
+ * @type {number}
+ */
+webCrypto.AesCtrParams.prototype.length;
+
+
+/**
+ * @record
+ * @extends webCrypto.KeyAlgorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-AesKeyAlgorithm
+ */
+webCrypto.AesKeyAlgorithm;
+/**
+ * @type {number}
+ */
+webCrypto.AesKeyAlgorithm.prototype.length;
+
+
+/**
+ * @record
+ * @extends webCrypto.Algorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-AesKeyGenParams
+ */
+webCrypto.AesKeyGenParams;
+/**
+ * @type {number}
+ */
+webCrypto.AesKeyGenParams.prototype.length;
+
+
+/**
+ * @record
+ * @extends webCrypto.Algorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-AesDerivedKeyParams
+ */
+webCrypto.AesDerivedKeyParams;
+/**
+ * @type {number}
+ */
+webCrypto.AesDerivedKeyParams.prototype.length;
+
+
+/**
+ * @record
+ * @extends webCrypto.Algorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-AesCbcParams
+ */
+webCrypto.AesCbcParams;
+/**
+ * @type {!BufferSource}
+ */
+webCrypto.AesCbcParams.prototype.iv;
+
+
+/**
+ * @record
+ * @extends webCrypto.Algorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-AesGcmParams
+ */
+webCrypto.AesGcmParams;
+/**
+ * @type {!BufferSource}
+ */
+webCrypto.AesGcmParams.prototype.iv;
+/**
+ * @type {!BufferSource}
+ */
+webCrypto.AesGcmParams.prototype.additionalData;
+/**
+ * @type {number}
+ */
+webCrypto.AesGcmParams.prototype.tagLength;
+
+
+/**
+ * @record
+ * @extends webCrypto.Algorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-HmacImportParams
+ */
+webCrypto.HmacImportParams;
+/**
+ * @type {!webCrypto.HashAlgorithmIdentifier}
+ */
+webCrypto.HmacImportParams.prototype.hash;
+/**
+ * @type {number}
+ */
+webCrypto.HmacImportParams.prototype.length;
+
+
+/**
+ * @record
+ * @extends webCrypto.KeyAlgorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-HmacKeyAlgorithm
+ */
+webCrypto.HmacKeyAlgorithm;
+/**
+ * @type {!webCrypto.KeyAlgorithm}
+ */
+webCrypto.HmacKeyAlgorithm.prototype.hash;
+/**
+ * @type {number}
+ */
+webCrypto.HmacKeyAlgorithm.prototype.length;
+
+
+/**
+ * @record
+ * @extends webCrypto.Algorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-HmacKeyGenParams
+ */
+webCrypto.HmacKeyGenParams;
+/**
+ * @type {!webCrypto.HashAlgorithmIdentifier}
+ */
+webCrypto.HmacKeyGenParams.prototype.hash;
+/**
+ * @type {number}
+ */
+webCrypto.HmacKeyGenParams.prototype.length;
+
+
+/**
+ * @record
+ * @extends webCrypto.Algorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-HkdfParams
+ */
+webCrypto.HkdfParams;
+/**
+ * @type {!webCrypto.HashAlgorithmIdentifier}
+ */
+webCrypto.HkdfParams.prototype.hash;
+/**
+ * @type {!BufferSource}
+ */
+webCrypto.HkdfParams.prototype.salt;
+/**
+ * @type {!BufferSource}
+ */
+webCrypto.HkdfParams.prototype.info;
+
+
+/**
+ * @record
+ * @extends webCrypto.Algorithm
+ * @see https://www.w3.org/TR/WebCryptoAPI/#dfn-Pbkdf2Params
+ */
+webCrypto.Pbkdf2Params;
+/**
+ * @type {!BufferSource}
+ */
+webCrypto.Pbkdf2Params.prototype.salt;
+/**
+ * @type {number}
+ */
+webCrypto.Pbkdf2Params.prototype.iterations;
+/**
+ * @type {!webCrypto.HashAlgorithmIdentifier}
+ */
+webCrypto.Pbkdf2Params.prototype.hash;
+
+
 /**
  * @constructor
  * @see http://www.w3.org/TR/WebCryptoAPI/#subtlecrypto-interface
@@ -260,8 +623,8 @@ webCrypto.SubtleCrypto = function() {};
  *     values are: AES-CBC, AES-CTR, AES-GCM, and RSA-OAEP.
  * @param {!webCrypto.CryptoKey} key Key to be used for signing.
  * @param {!BufferSource} data Data to be encrypted (cleartext).
- * @return {!Promise<*>} Ciphertext generated by the encryption of the
- *     cleartext.
+ * @return {!Promise<!ArrayBuffer>} Ciphertext generated by the encryption of
+ *     the cleartext.
  */
 webCrypto.SubtleCrypto.prototype.encrypt = function(algorithm, key,
     data) {};
@@ -272,7 +635,7 @@ webCrypto.SubtleCrypto.prototype.encrypt = function(algorithm, key,
  *     values are: AES-CBC, AES-CTR, AES-GCM, and RSA-OAEP.
  * @param {!webCrypto.CryptoKey} key Key to be used for signing.
  * @param {!BufferSource} data Data to be decrypted (ciphertext).
- * @return {!Promise<*>} Cleartext generated by the decryption of the
+ * @return {!Promise<!ArrayBuffer>} Cleartext generated by the decryption of the
  *     ciphertext.
  */
 webCrypto.SubtleCrypto.prototype.decrypt = function(algorithm, key,
@@ -284,7 +647,7 @@ webCrypto.SubtleCrypto.prototype.decrypt = function(algorithm, key,
  *     values are: HMAC, RSASSA-PKCS1-v1_5, and ECDSA.
  * @param {!webCrypto.CryptoKey} key Private key to be used for signing.
  * @param {!BufferSource} data Data to be signed.
- * @return {!Promise<*>} Returns the signature on success.
+ * @return {!Promise<!ArrayBuffer>} Returns the signature on success.
  */
 webCrypto.SubtleCrypto.prototype.sign = function(algorithm, key,
     data) {};
@@ -296,8 +659,8 @@ webCrypto.SubtleCrypto.prototype.sign = function(algorithm, key,
  * @param {!webCrypto.CryptoKey} key Private key to be used for signing.
  * @param {!BufferSource} signature Signature to verify.
  * @param {!BufferSource} data Data whose signature needs to be verified.
- * @return {!Promise<*>} Returns a boolean indicating if the signature operating
- *     has been successful.
+ * @return {!Promise<boolean>} Returns if the signature operating has been
+ *     successful.
  */
 webCrypto.SubtleCrypto.prototype.verify = function(algorithm, key,
     signature, data) {};
@@ -307,21 +670,21 @@ webCrypto.SubtleCrypto.prototype.verify = function(algorithm, key,
  * @param {!webCrypto.AlgorithmIdentifier} algorithm Supported
  *     values are: SHA-1, SHA-256, SHA-384, and SHA-512.
  * @param {!BufferSource} data Data to be hashed using the hashing algorithm.
- * @return {!Promise<*>} returns the hash on success.
+ * @return {!Promise<!ArrayBuffer>} returns the hash on success.
  */
 webCrypto.SubtleCrypto.prototype.digest = function(algorithm, data) {};
 
 
 /**
- * @param {!webCrypto.AlgorithmIdentifier} algorithm Supported
- *     values are: SHA-1, SHA-256, SHA-384, and SHA-512.
+ * @param {!webCrypto.AlgorithmIdentifier|webCrypto.RsaHashedKeyGenParams}
+ *     algorithm Supported values are: SHA-1, SHA-256, SHA-384, and SHA-512.
  * @param {boolean} extractable If the key can be extracted from the CryptoKey
  *     object at a later stage.
  * @param {!Array<string>} keyUsages Indication of new key options i.e.
  *     encrypt, decrypt, sign, verify, deriveKey, deriveBits, wrapKey,
  *     unwrapKey.
- * @return {!Promise<*>} returns the generated key as a CryptoKey or a
- *     CryptoKeyPair.
+ * @return {!Promise<!webCrypto.CryptoKey|!webCrypto.CryptoKeyPair>} returns the
+ *     generated key.
  */
 webCrypto.SubtleCrypto.prototype.generateKey = function(algorithm,
     extractable, keyUsages) {};
@@ -338,8 +701,8 @@ webCrypto.SubtleCrypto.prototype.generateKey = function(algorithm,
  *     CryptoKey object at a later stage.
  * @param {!Array<string>} keyUsages Indicates what can be done with the
  *     derivated key.
- * @return {!Promise<*>} returns the generated key as a CryptoKey or a
- *     CryptoKeyPair.
+ * @return {!Promise<!webCrypto.CryptoKey|!webCrypto.CryptoKeyPair>} returns the
+ *     generated key.
  */
 webCrypto.SubtleCrypto.prototype.deriveKey = function(algorithm,
    baseKey, derivedKeyAlgo, extractable, keyUsages) {};
@@ -351,8 +714,7 @@ webCrypto.SubtleCrypto.prototype.deriveKey = function(algorithm,
  * @param {!webCrypto.CryptoKey} baseKey Key to be used by the key
  *     derivation algorithm.
  * @param {number} length
- * @return {!Promise<*>} returns the generated key as a CryptoKey or a
- *     CryptoKeyPair.
+ * @return {!Promise<!ArrayBuffer>} returns the generated bits.
  */
 webCrypto.SubtleCrypto.prototype.deriveBits = function(algorithm,
    baseKey, length) {};
@@ -363,15 +725,15 @@ webCrypto.SubtleCrypto.prototype.deriveBits = function(algorithm,
  *     format of the key to imported.
  * @param {!BufferSource|!webCrypto.JsonWebKey} keyData The key
  *     in the given format.
- * @param {!webCrypto.AlgorithmIdentifier} algorithm Supported values
- *     are: AES-CTR, AES-CBC, AES-GCM, RSA-OAEP, AES-KW, HMAC,
- *     RSASSA-PKCS1-v1_5, ECDSA, ECDH, DH.
+ * @param {!webCrypto.AlgorithmIdentifier|webCrypto.RsaHashedImportParams}
+ *     algorithm Supported values are: AES-CTR, AES-CBC, AES-GCM, RSA-OAEP,
+ *     AES-KW, HMAC, RSASSA-PKCS1-v1_5, ECDSA, ECDH, DH.
  * @param {boolean} extractable If the key can be extracted from the CryptoKey
  *     object at a later stage.
  * @param {!Array<string>} keyUsages Indication of new key options i.e.
  *     encrypt, decrypt, sign, verify, deriveKey, deriveBits, wrapKey,
  *     unwrapKey.
- * @return {!Promise<*>} returns the generated key as a CryptoKey.
+ * @return {!Promise<!webCrypto.CryptoKey>} returns the generated key.
  */
 webCrypto.SubtleCrypto.prototype.importKey = function(format, keyData,
     algorithm, extractable, keyUsages) {};
@@ -381,7 +743,8 @@ webCrypto.SubtleCrypto.prototype.importKey = function(format, keyData,
  * @param {string} format Enumerated value describing the data
  *     format of the key to imported.
  * @param {!webCrypto.CryptoKey} key CryptoKey to export.
- * @return {!Promise<*>} returns the key in the requested format.
+ * @return {!Promise<!ArrayBuffer|!webCrypto.JsonWebKey>} returns the key in the
+ *     requested format.
  */
 webCrypto.SubtleCrypto.prototype.exportKey = function(format, key) {};
 
@@ -395,7 +758,8 @@ webCrypto.SubtleCrypto.prototype.exportKey = function(format, key) {};
  * @param {!webCrypto.AlgorithmIdentifier} wrapAlgorithm algorithm used
  *     to perform the wrapping. It is one of the following: AES-CBC, AES-CTR,
  *     AES-GCM, RSA-OAEP, and AES-KW.
- * @return {!Promise<*>} returns the wrapped key in the requested format.
+ * @return {!Promise<!ArrayBuffer>} returns the wrapped key in the requested
+ *     format.
  */
 webCrypto.SubtleCrypto.prototype.wrapKey = function(format,
    key, wrappingKey, wrapAlgorithm) {};
@@ -417,7 +781,7 @@ webCrypto.SubtleCrypto.prototype.wrapKey = function(format,
  *     CryptoKey object at a later stage.
  * @param {!Array<string>} keyUsages Indicates what can be done with the
  *     derivated key.
- * @return {!Promise<*>} returns the unwrapped key as a CryptoKey.
+ * @return {!Promise<!webCrypto.CryptoKey>} returns the unwrapped key.
  */
 webCrypto.SubtleCrypto.prototype.unwrapKey = function(format, wrappedKey,
     unwrappingKey, unwrapAlgorithm, unwrappedKeyAlgorithm, extractable,
@@ -425,13 +789,10 @@ webCrypto.SubtleCrypto.prototype.unwrapKey = function(format, wrappedKey,
 
 
 /**
- * Web Cryptography API
- * @see http://www.w3.org/TR/WebCryptoAPI/
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/Crypto
+ * @interface
  */
-
-/** @see https://developer.mozilla.org/en/DOM/window.crypto */
-Window.prototype.crypto;
-
+webCrypto.Crypto = function() {};
 
 /**
  * @see https://developer.mozilla.org/en/DOM/window.crypto.getRandomValues
@@ -439,11 +800,16 @@ Window.prototype.crypto;
  * @return {!ArrayBufferView}
  * @throws {Error}
  */
-Window.prototype.crypto.getRandomValues = function(typedArray) {};
-
+webCrypto.Crypto.prototype.getRandomValues = function(typedArray) {};
 
 /**
- * @type {webCrypto.SubtleCrypto}
+ * @type {?webCrypto.SubtleCrypto}
  * @see http://www.w3.org/TR/WebCryptoAPI/#Crypto-attribute-subtle
  */
-Window.prototype.crypto.subtle;
+webCrypto.Crypto.prototype.subtle;
+
+/**
+ * @see https://developer.mozilla.org/en/DOM/window.crypto
+ * @type {!webCrypto.Crypto|undefined}
+ */
+var crypto;
diff --git a/javascript/externs/web/w3c_xml.js b/javascript/externs/web/w3c_xml.js
index e1a57dcae99d..0cd0effc23f1 100644
--- a/javascript/externs/web/w3c_xml.js
+++ b/javascript/externs/web/w3c_xml.js
@@ -25,8 +25,7 @@
  *    XMLHttpRequest - Fully type annotated
  *
  * @see http://www.w3.org/TR/DOM-Level-3-XPath/xpath.html
- * @see http://www.w3.org/TR/XMLHttpRequest/
- * @see http://www.w3.org/TR/XMLHttpRequest2/
+ * @see https://xhr.spec.whatwg.org/
  *
  * @externs
  * @author stevey@google.com (Steve Yegge)
@@ -40,16 +39,16 @@
 function XPathException() {}
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-XPath/xpath.html#INVALID_EXPRESSION_ERR
  */
-XPathException.INVALID_EXPRESSION_ERR = 52;
+XPathException.INVALID_EXPRESSION_ERR;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-XPath/xpath.html#TYPE_ERR
  */
-XPathException.TYPE_ERR = 52;
+XPathException.TYPE_ERR;
 
 /**
  * @type {number}
@@ -133,7 +132,6 @@ XPathNSResolver.prototype.lookupNamespaceURI = function(prefix) {};
  * XPath is a language for addressing parts of an XML document, designed to be
  * used by both XSLT and XPointer.
  *
- * @noalias
  * @constructor
  * @see http://www.w3.org/TR/DOM-Level-3-XPath/xpath.html#XPathResult
  */
@@ -203,64 +201,64 @@ XPathResult.prototype.iterateNext = function() {};
 XPathResult.prototype.snapshotItem = function(index) {};
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-XPath/xpath.html#XPathResult-ANY-TYPE
  */
-XPathResult.ANY_TYPE = 0;
+XPathResult.ANY_TYPE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-XPath/xpath.html#XPathResult-NUMBER-TYPE
  */
-XPathResult.NUMBER_TYPE = 1;
+XPathResult.NUMBER_TYPE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-XPath/xpath.html#XPathResult-STRING-TYPE
  */
-XPathResult.STRING_TYPE = 2;
+XPathResult.STRING_TYPE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-XPath/xpath.html#XPathResult-BOOLEAN-TYPE
  */
-XPathResult.BOOLEAN_TYPE = 3;
+XPathResult.BOOLEAN_TYPE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-XPath/xpath.html#XPathResult-UNORDERED-NODE-ITERATOR-TYPE
  */
-XPathResult.UNORDERED_NODE_ITERATOR_TYPE = 4;
+XPathResult.UNORDERED_NODE_ITERATOR_TYPE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-XPath/xpath.html#XPathResult-ORDERED-NODE-ITERATOR-TYPE
  */
-XPathResult.ORDERED_NODE_ITERATOR_TYPE = 5;
+XPathResult.ORDERED_NODE_ITERATOR_TYPE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-XPath/xpath.html#XPathResult-UNORDERED-NODE-SNAPSHOT-TYPE
  */
-XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE = 6;
+XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-XPath/xpath.html#XPathResult-ORDERED-NODE-SNAPSHOT-TYPE
  */
-XPathResult.ORDERED_NODE_SNAPSHOT_TYPE = 7;
+XPathResult.ORDERED_NODE_SNAPSHOT_TYPE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-XPath/xpath.html#XPathResult-ANY-UNORDERED-NODE-TYPE
  */
-XPathResult.ANY_UNORDERED_NODE_TYPE = 8;
+XPathResult.ANY_UNORDERED_NODE_TYPE;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-XPath/xpath.html#XPathResult-FIRST-ORDERED-NODE-TYPE
  */
-XPathResult.FIRST_ORDERED_NODE_TYPE = 9;
+XPathResult.FIRST_ORDERED_NODE_TYPE;
 
 /**
  * @constructor
@@ -276,13 +274,13 @@ function XPathNamespace() {}
 XPathNamespace.prototype.ownerElement;
 
 /**
- * @type {number}
+ * @const {number}
  * @see http://www.w3.org/TR/DOM-Level-3-XPath/xpath.html#XPATH_NAMESPACE_NODE
  */
-XPathNamespace.XPATH_NAMESPACE_NODE = 13;
+XPathNamespace.XPATH_NAMESPACE_NODE;
 
 /**
- * From http://www.w3.org/TR/XMLHttpRequest/
+ * From https://xhr.spec.whatwg.org/#xmlhttprequest
  *
  * (Draft)
  *
@@ -292,30 +290,19 @@ XPathNamespace.XPATH_NAMESPACE_NODE = 13;
  *
  * @constructor
  * @implements {EventTarget}
- * @see http://www.w3.org/TR/XMLHttpRequest/#xmlhttprequest-object
+ * @see https://xhr.spec.whatwg.org/#xmlhttprequest
  */
 function XMLHttpRequest() {}
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-XMLHttpRequest.prototype.addEventListener =
-    function(type, listener, opt_useCapture) {};
+/** @override */
+XMLHttpRequest.prototype.addEventListener = function(
+    type, listener, opt_options) {};
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-XMLHttpRequest.prototype.removeEventListener =
-    function(type, listener, opt_useCapture) {};
+/** @override */
+XMLHttpRequest.prototype.removeEventListener = function(
+    type, listener, opt_options) {};
 
-/**
- * @override
- * @return {boolean}
- */
+/** @override */
 XMLHttpRequest.prototype.dispatchEvent = function(evt) {};
 
 /**
@@ -325,7 +312,7 @@ XMLHttpRequest.prototype.dispatchEvent = function(evt) {};
  * @param {?string=} opt_user
  * @param {?string=} opt_password
  * @return {undefined}
- * @see http://www.w3.org/TR/XMLHttpRequest/#the-open()-method
+ * @see https://xhr.spec.whatwg.org/#the-open()-method
  */
 XMLHttpRequest.prototype.open = function(method, url, opt_async, opt_user,
     opt_password) {};
@@ -334,130 +321,213 @@ XMLHttpRequest.prototype.open = function(method, url, opt_async, opt_user,
  * @param {string} header
  * @param {string} value
  * @return {undefined}
- * @see http://www.w3.org/TR/XMLHttpRequest/#the-setrequestheader()-method
+ * @see https://xhr.spec.whatwg.org/#the-setrequestheader()-method
  */
 XMLHttpRequest.prototype.setRequestHeader = function(header, value) {};
 
 /**
  * @param {ArrayBuffer|ArrayBufferView|Blob|Document|FormData|string=} opt_data
  * @return {undefined}
- * @see http://www.w3.org/TR/XMLHttpRequest/#the-send()-method
+ * @see https://xhr.spec.whatwg.org/#the-send()-method
  */
 XMLHttpRequest.prototype.send = function(opt_data) {};
 
 /**
  * @return {undefined}
- * @see http://www.w3.org/TR/XMLHttpRequest/#the-abort()-method
+ * @see https://xhr.spec.whatwg.org/#the-abort()-method
  */
 XMLHttpRequest.prototype.abort = function() {};
 
 /**
  * @return {string}
- * @see http://www.w3.org/TR/XMLHttpRequest/#the-getallresponseheaders()-method
+ * @see https://xhr.spec.whatwg.org/#the-getallresponseheaders()-method
  */
 XMLHttpRequest.prototype.getAllResponseHeaders = function() {};
 
 /**
  * @param {string} header
- * @return {string}
- * @see http://www.w3.org/TR/XMLHttpRequest/#the-getresponseheader()-method
+ * @return {?string}
+ * @see https://xhr.spec.whatwg.org/#the-getresponseheader()-method
  */
 XMLHttpRequest.prototype.getResponseHeader = function(header) {};
 
 /**
  * @type {string}
- * @see http://www.w3.org/TR/XMLHttpRequest/#the-responsetext-attribute
+ * @see https://xhr.spec.whatwg.org/#the-responsetext-attribute
  */
 XMLHttpRequest.prototype.responseText;
 
 /**
  * This is not supported in any IE browser (as of August 2016).
  * @type {string}
- * @see https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/responseURL
+ * @see https://xhr.spec.whatwg.org/#the-responseurl-attribute
  */
 XMLHttpRequest.prototype.responseURL;
 
 /**
  * @type {Document}
- * @see http://www.w3.org/TR/XMLHttpRequest/#the-responsexml-attribute
+ * @see https://xhr.spec.whatwg.org/#the-responsexml-attribute
  */
 XMLHttpRequest.prototype.responseXML;
 
 /**
  * @type {number}
- * @see http://www.w3.org/TR/XMLHttpRequest/#the-readystate-attribute
+ * @see https://xhr.spec.whatwg.org/#dom-xmlhttprequest-readystate
  */
 XMLHttpRequest.prototype.readyState;
 
 /**
  * @type {number}
- * @see http://www.w3.org/TR/XMLHttpRequest/#the-status-attribute
+ * @see https://xhr.spec.whatwg.org/#the-status-attribute
  */
 XMLHttpRequest.prototype.status;
 
 /**
  * @type {string}
- * @see http://www.w3.org/TR/XMLHttpRequest/#the-statustext-attribute
+ * @see https://xhr.spec.whatwg.org/#the-statustext-attribute
  */
 XMLHttpRequest.prototype.statusText;
 
 /**
- * @type {Function}
- * @see http://www.w3.org/TR/XMLHttpRequest/#handler-xhr-onreadystatechange
+ * @type {number}
+ * @see https://xhr.spec.whatwg.org/#the-timeout-attribute
+ */
+XMLHttpRequest.prototype.timeout;
+
+/**
+ * @type {?function(!Event)}
+ * @see https://xhr.spec.whatwg.org/#event-handlers
  */
 XMLHttpRequest.prototype.onreadystatechange;
 
 /**
- * @type {Function}
- * @see http://www.w3.org/TR/XMLHttpRequest/#handler-xhr-onerror
+ * @type {?function(!Event)}
+ * @see https://xhr.spec.whatwg.org/#event-handlers
  */
 XMLHttpRequest.prototype.onerror;
 
 /**
- * @type {number}
- * @see https://www.w3.org/TR/XMLHttpRequest/#states
+ * @const {number}
+ * @see https://xhr.spec.whatwg.org/#states
  */
 XMLHttpRequest.UNSENT;
 
 /**
- * @type {number}
- * @see https://www.w3.org/TR/XMLHttpRequest/#states
+ * @const {number}
+ * @see https://xhr.spec.whatwg.org/#states
+ */
+XMLHttpRequest.prototype.UNSENT;
+
+/**
+ * @const {number}
+ * @see https://xhr.spec.whatwg.org/#states
  */
 XMLHttpRequest.OPENED;
 
 /**
- * @type {number}
- * @see https://www.w3.org/TR/XMLHttpRequest/#states
+ * @const {number}
+ * @see https://xhr.spec.whatwg.org/#states
+ */
+XMLHttpRequest.prototype.OPENED;
+
+/**
+ * @const {number}
+ * @see https://xhr.spec.whatwg.org/#states
  */
 XMLHttpRequest.HEADERS_RECEIVED;
 
 /**
- * @type {number}
- * @see https://www.w3.org/TR/XMLHttpRequest/#states
+ * @const {number}
+ * @see https://xhr.spec.whatwg.org/#states
+ */
+XMLHttpRequest.prototype.HEADERS_RECEIVED;
+
+/**
+ * @const {number}
+ * @see https://xhr.spec.whatwg.org/#states
  */
 XMLHttpRequest.LOADING;
 
 /**
- * @type {number}
- * @see https://www.w3.org/TR/XMLHttpRequest/#states
+ * @const {number}
+ * @see https://xhr.spec.whatwg.org/#states
+ */
+XMLHttpRequest.prototype.LOADING;
+
+/**
+ * @const {number}
+ * @see https://xhr.spec.whatwg.org/#states
  */
 XMLHttpRequest.DONE;
 
+/**
+ * @const {number}
+ * @see https://xhr.spec.whatwg.org/#states
+ */
+XMLHttpRequest.prototype.DONE;
+
+
+/**
+ * @see https://xhr.spec.whatwg.org/#formdataentryvalue
+ * @typedef {!File|string}
+ */
+var FormDataEntryValue;
+
 /**
  * The FormData object represents an ordered collection of entries. Each entry
  * has a name and value.
  *
- * @param {?Element=} opt_form An optional form to use for constructing the form
+ * @param {?Element=} form An optional form to use for constructing the form
  *     data set.
  * @constructor
- * @see http://www.w3.org/TR/XMLHttpRequest2/#the-formdata-interface
+ * @implements {Iterable<!Array<!FormDataEntryValue>>}
+ * @see https://xhr.spec.whatwg.org/#interface-formdata
+ */
+function FormData(form) {}
+
+/**
+ * @param {string} name
+ * @param {?Blob|string} value
+ * @param {string=} filename
+ * @return {undefined}
+ * @see https://xhr.spec.whatwg.org/#dom-formdata-append
  */
-function FormData(opt_form) {}
+FormData.prototype.append = function(name, value, filename) {};
 
 /**
  * @param {string} name
- * @param {Blob|string} value
- * @param {string=} opt_filename
  * @return {undefined}
+ * @see https://xhr.spec.whatwg.org/#dom-formdata-delete
  */
-FormData.prototype.append = function(name, value, opt_filename) {};
+FormData.prototype.delete = function(name) {};
+
+/**
+ * @param {string} name
+ * @return {?FormDataEntryValue}
+ * @see https://xhr.spec.whatwg.org/#dom-formdata-get
+ */
+FormData.prototype.get = function(name) {};
+
+/**
+ * @param {string} name
+ * @return {!Array<!FormDataEntryValue>}
+ * @see https://xhr.spec.whatwg.org/#dom-formdata-getall
+ */
+FormData.prototype.getAll = function(name) {};
+
+/**
+ * @param {string} name
+ * @return {boolean}
+ * @see https://xhr.spec.whatwg.org/#dom-formdata-has
+ */
+FormData.prototype.has = function(name) {};
+
+/**
+ * @param {string} name
+ * @param {!Blob|string} value
+ * @param {string=} filename
+ * @return {undefined}
+ * @see https://xhr.spec.whatwg.org/#dom-formdata-set
+ */
+FormData.prototype.set = function(name, value, filename) {};
+
diff --git a/javascript/externs/web/webgl.js b/javascript/externs/web/webgl.js
index df0b2557e618..fc3d9f5b7066 100644
--- a/javascript/externs/web/webgl.js
+++ b/javascript/externs/web/webgl.js
@@ -29,1788 +29,1793 @@
  */
 
 
+/**
+ * @typedef {ImageBitmap|ImageData|HTMLImageElement|HTMLCanvasElement|
+ *     HTMLVideoElement|OffscreenCanvas}
+ */
+var TexImageSource;
+
 /**
  * @constructor
- * @noalias
  */
 function WebGLRenderingContext() {}
 
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DEPTH_BUFFER_BIT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_BUFFER_BIT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.COLOR_BUFFER_BIT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.POINTS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.LINES;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.LINE_LOOP;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.LINE_STRIP;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TRIANGLES;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TRIANGLE_STRIP;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TRIANGLE_FAN;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ZERO;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ONE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.SRC_COLOR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ONE_MINUS_SRC_COLOR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.SRC_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ONE_MINUS_SRC_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DST_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ONE_MINUS_DST_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DST_COLOR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ONE_MINUS_DST_COLOR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.SRC_ALPHA_SATURATE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FUNC_ADD;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BLEND_EQUATION;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BLEND_EQUATION_RGB;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BLEND_EQUATION_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FUNC_SUBTRACT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FUNC_REVERSE_SUBTRACT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BLEND_DST_RGB;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BLEND_SRC_RGB;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BLEND_DST_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BLEND_SRC_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.CONSTANT_COLOR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ONE_MINUS_CONSTANT_COLOR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.CONSTANT_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ONE_MINUS_CONSTANT_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BLEND_COLOR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ARRAY_BUFFER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ELEMENT_ARRAY_BUFFER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ARRAY_BUFFER_BINDING;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ELEMENT_ARRAY_BUFFER_BINDING;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STREAM_DRAW;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STATIC_DRAW;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DYNAMIC_DRAW;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BUFFER_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BUFFER_USAGE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.CURRENT_VERTEX_ATTRIB;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FRONT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BACK;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FRONT_AND_BACK;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.CULL_FACE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BLEND;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DITHER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_TEST;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DEPTH_TEST;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.SCISSOR_TEST;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.POLYGON_OFFSET_FILL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.SAMPLE_ALPHA_TO_COVERAGE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.SAMPLE_COVERAGE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.NO_ERROR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.INVALID_ENUM;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.INVALID_VALUE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.INVALID_OPERATION;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.OUT_OF_MEMORY;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.CW;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.CCW;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.LINE_WIDTH;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ALIASED_POINT_SIZE_RANGE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ALIASED_LINE_WIDTH_RANGE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.CULL_FACE_MODE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FRONT_FACE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DEPTH_RANGE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DEPTH_WRITEMASK;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DEPTH_CLEAR_VALUE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DEPTH_FUNC;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_CLEAR_VALUE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_FUNC;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_FAIL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_PASS_DEPTH_FAIL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_PASS_DEPTH_PASS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_REF;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_VALUE_MASK;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_WRITEMASK;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_BACK_FUNC;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_BACK_FAIL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_BACK_PASS_DEPTH_FAIL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_BACK_PASS_DEPTH_PASS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_BACK_REF;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_BACK_VALUE_MASK;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_BACK_WRITEMASK;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.VIEWPORT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.SCISSOR_BOX;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.COLOR_CLEAR_VALUE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.COLOR_WRITEMASK;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.UNPACK_ALIGNMENT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.PACK_ALIGNMENT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.MAX_TEXTURE_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.MAX_VIEWPORT_DIMS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.SUBPIXEL_BITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.RED_BITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.GREEN_BITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BLUE_BITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ALPHA_BITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DEPTH_BITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_BITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.POLYGON_OFFSET_UNITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.POLYGON_OFFSET_FACTOR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE_BINDING_2D;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.SAMPLE_BUFFERS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.SAMPLES;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.SAMPLE_COVERAGE_VALUE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.SAMPLE_COVERAGE_INVERT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.COMPRESSED_TEXTURE_FORMATS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DONT_CARE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FASTEST;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.NICEST;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.GENERATE_MIPMAP_HINT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BYTE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.UNSIGNED_BYTE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.SHORT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.UNSIGNED_SHORT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.INT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.UNSIGNED_INT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FLOAT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DEPTH_COMPONENT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.RGB;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.RGBA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.LUMINANCE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.LUMINANCE_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.UNSIGNED_SHORT_4_4_4_4;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.UNSIGNED_SHORT_5_5_5_1;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.UNSIGNED_SHORT_5_6_5;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FRAGMENT_SHADER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.VERTEX_SHADER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.MAX_VERTEX_ATTRIBS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.MAX_VERTEX_UNIFORM_VECTORS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.MAX_VARYING_VECTORS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.MAX_COMBINED_TEXTURE_IMAGE_UNITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.MAX_VERTEX_TEXTURE_IMAGE_UNITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.MAX_TEXTURE_IMAGE_UNITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.MAX_FRAGMENT_UNIFORM_VECTORS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.SHADER_TYPE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DELETE_STATUS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.LINK_STATUS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.VALIDATE_STATUS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ATTACHED_SHADERS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ACTIVE_UNIFORMS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ACTIVE_ATTRIBUTES;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.SHADING_LANGUAGE_VERSION;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.CURRENT_PROGRAM;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.NEVER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.LESS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.EQUAL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.LEQUAL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.GREATER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.NOTEQUAL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.GEQUAL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ALWAYS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.KEEP;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.REPLACE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.INCR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DECR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.INVERT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.INCR_WRAP;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DECR_WRAP;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.VENDOR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.RENDERER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.VERSION;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.NEAREST;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.LINEAR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.NEAREST_MIPMAP_NEAREST;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.LINEAR_MIPMAP_NEAREST;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.NEAREST_MIPMAP_LINEAR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.LINEAR_MIPMAP_LINEAR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE_MAG_FILTER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE_MIN_FILTER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE_WRAP_S;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE_WRAP_T;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE_2D;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE_CUBE_MAP;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE_BINDING_CUBE_MAP;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE_CUBE_MAP_POSITIVE_X;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE_CUBE_MAP_NEGATIVE_X;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE_CUBE_MAP_POSITIVE_Y;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE_CUBE_MAP_NEGATIVE_Y;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE_CUBE_MAP_POSITIVE_Z;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE_CUBE_MAP_NEGATIVE_Z;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.MAX_CUBE_MAP_TEXTURE_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE0;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE1;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE2;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE3;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE4;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE5;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE6;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE7;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE8;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE9;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE10;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE11;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE12;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE13;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE14;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE15;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE16;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE17;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE18;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE19;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE20;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE21;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE22;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE23;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE24;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE25;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE26;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE27;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE28;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE29;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE30;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.TEXTURE31;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.ACTIVE_TEXTURE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.REPEAT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.CLAMP_TO_EDGE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.MIRRORED_REPEAT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FLOAT_VEC2;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FLOAT_VEC3;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FLOAT_VEC4;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.INT_VEC2;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.INT_VEC3;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.INT_VEC4;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BOOL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BOOL_VEC2;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BOOL_VEC3;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BOOL_VEC4;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FLOAT_MAT2;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FLOAT_MAT3;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FLOAT_MAT4;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.SAMPLER_2D;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.SAMPLER_CUBE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.VERTEX_ATTRIB_ARRAY_ENABLED;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.VERTEX_ATTRIB_ARRAY_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.VERTEX_ATTRIB_ARRAY_STRIDE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.VERTEX_ATTRIB_ARRAY_TYPE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.VERTEX_ATTRIB_ARRAY_NORMALIZED;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.VERTEX_ATTRIB_ARRAY_POINTER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.VERTEX_ATTRIB_ARRAY_BUFFER_BINDING;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.IMPLEMENTATION_COLOR_READ_FORMAT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.IMPLEMENTATION_COLOR_READ_TYPE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.COMPILE_STATUS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.LOW_FLOAT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.MEDIUM_FLOAT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.HIGH_FLOAT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.LOW_INT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.MEDIUM_INT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.HIGH_INT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FRAMEBUFFER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.RENDERBUFFER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.RGBA4;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.RGB5_A1;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.RGB565;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DEPTH_COMPONENT16;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_INDEX;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_INDEX8;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DEPTH_STENCIL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.RENDERBUFFER_WIDTH;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.RENDERBUFFER_HEIGHT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.RENDERBUFFER_INTERNAL_FORMAT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.RENDERBUFFER_RED_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.RENDERBUFFER_GREEN_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.RENDERBUFFER_BLUE_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.RENDERBUFFER_ALPHA_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.RENDERBUFFER_DEPTH_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.RENDERBUFFER_STENCIL_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FRAMEBUFFER_ATTACHMENT_OBJECT_NAME;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FRAMEBUFFER_ATTACHMENT_TEXTURE_CUBE_MAP_FACE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.COLOR_ATTACHMENT0;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DEPTH_ATTACHMENT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.STENCIL_ATTACHMENT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.DEPTH_STENCIL_ATTACHMENT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.NONE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FRAMEBUFFER_COMPLETE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FRAMEBUFFER_INCOMPLETE_DIMENSIONS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FRAMEBUFFER_UNSUPPORTED;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.FRAMEBUFFER_BINDING;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.RENDERBUFFER_BINDING;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.MAX_RENDERBUFFER_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.INVALID_FRAMEBUFFER_OPERATION;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.UNPACK_FLIP_Y_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.UNPACK_PREMULTIPLY_ALPHA_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.CONTEXT_LOST_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.UNPACK_COLORSPACE_CONVERSION_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.BROWSER_DEFAULT_WEBGL;
 
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DEPTH_BUFFER_BIT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_BUFFER_BIT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.COLOR_BUFFER_BIT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.POINTS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.LINES;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.LINE_LOOP;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.LINE_STRIP;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TRIANGLES;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TRIANGLE_STRIP;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TRIANGLE_FAN;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ZERO;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ONE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.SRC_COLOR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ONE_MINUS_SRC_COLOR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.SRC_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ONE_MINUS_SRC_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DST_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ONE_MINUS_DST_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DST_COLOR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ONE_MINUS_DST_COLOR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.SRC_ALPHA_SATURATE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FUNC_ADD;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BLEND_EQUATION;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BLEND_EQUATION_RGB;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BLEND_EQUATION_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FUNC_SUBTRACT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FUNC_REVERSE_SUBTRACT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BLEND_DST_RGB;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BLEND_SRC_RGB;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BLEND_DST_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BLEND_SRC_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.CONSTANT_COLOR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ONE_MINUS_CONSTANT_COLOR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.CONSTANT_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ONE_MINUS_CONSTANT_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BLEND_COLOR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ARRAY_BUFFER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ELEMENT_ARRAY_BUFFER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ARRAY_BUFFER_BINDING;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ELEMENT_ARRAY_BUFFER_BINDING;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STREAM_DRAW;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STATIC_DRAW;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DYNAMIC_DRAW;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BUFFER_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BUFFER_USAGE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.CURRENT_VERTEX_ATTRIB;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FRONT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BACK;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FRONT_AND_BACK;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.CULL_FACE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BLEND;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DITHER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_TEST;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DEPTH_TEST;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.SCISSOR_TEST;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.POLYGON_OFFSET_FILL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.SAMPLE_ALPHA_TO_COVERAGE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.SAMPLE_COVERAGE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.NO_ERROR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.INVALID_ENUM;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.INVALID_VALUE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.INVALID_OPERATION;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.OUT_OF_MEMORY;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.CW;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.CCW;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.LINE_WIDTH;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ALIASED_POINT_SIZE_RANGE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ALIASED_LINE_WIDTH_RANGE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.CULL_FACE_MODE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FRONT_FACE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DEPTH_RANGE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DEPTH_WRITEMASK;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DEPTH_CLEAR_VALUE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DEPTH_FUNC;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_CLEAR_VALUE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_FUNC;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_FAIL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_PASS_DEPTH_FAIL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_PASS_DEPTH_PASS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_REF;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_VALUE_MASK;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_WRITEMASK;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_BACK_FUNC;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_BACK_FAIL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_BACK_PASS_DEPTH_FAIL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_BACK_PASS_DEPTH_PASS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_BACK_REF;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_BACK_VALUE_MASK;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_BACK_WRITEMASK;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.VIEWPORT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.SCISSOR_BOX;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.COLOR_CLEAR_VALUE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.COLOR_WRITEMASK;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.UNPACK_ALIGNMENT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.PACK_ALIGNMENT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.MAX_TEXTURE_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.MAX_VIEWPORT_DIMS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.SUBPIXEL_BITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.RED_BITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.GREEN_BITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BLUE_BITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ALPHA_BITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DEPTH_BITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_BITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.POLYGON_OFFSET_UNITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.POLYGON_OFFSET_FACTOR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE_BINDING_2D;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.SAMPLE_BUFFERS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.SAMPLES;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.SAMPLE_COVERAGE_VALUE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.SAMPLE_COVERAGE_INVERT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.COMPRESSED_TEXTURE_FORMATS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DONT_CARE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FASTEST;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.NICEST;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.GENERATE_MIPMAP_HINT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BYTE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.UNSIGNED_BYTE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.SHORT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.UNSIGNED_SHORT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.INT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.UNSIGNED_INT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FLOAT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DEPTH_COMPONENT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.RGB;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.RGBA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.LUMINANCE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.LUMINANCE_ALPHA;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.UNSIGNED_SHORT_4_4_4_4;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.UNSIGNED_SHORT_5_5_5_1;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.UNSIGNED_SHORT_5_6_5;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FRAGMENT_SHADER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.VERTEX_SHADER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.MAX_VERTEX_ATTRIBS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.MAX_VERTEX_UNIFORM_VECTORS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.MAX_VARYING_VECTORS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.MAX_COMBINED_TEXTURE_IMAGE_UNITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.MAX_VERTEX_TEXTURE_IMAGE_UNITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.MAX_TEXTURE_IMAGE_UNITS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.MAX_FRAGMENT_UNIFORM_VECTORS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.SHADER_TYPE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DELETE_STATUS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.LINK_STATUS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.VALIDATE_STATUS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ATTACHED_SHADERS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ACTIVE_UNIFORMS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ACTIVE_ATTRIBUTES;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.SHADING_LANGUAGE_VERSION;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.CURRENT_PROGRAM;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.NEVER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.LESS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.EQUAL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.LEQUAL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.GREATER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.NOTEQUAL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.GEQUAL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ALWAYS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.KEEP;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.REPLACE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.INCR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DECR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.INVERT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.INCR_WRAP;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DECR_WRAP;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.VENDOR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.RENDERER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.VERSION;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.NEAREST;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.LINEAR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.NEAREST_MIPMAP_NEAREST;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.LINEAR_MIPMAP_NEAREST;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.NEAREST_MIPMAP_LINEAR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.LINEAR_MIPMAP_LINEAR;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE_MAG_FILTER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE_MIN_FILTER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE_WRAP_S;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE_WRAP_T;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE_2D;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE_CUBE_MAP;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE_BINDING_CUBE_MAP;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE_CUBE_MAP_POSITIVE_X;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE_CUBE_MAP_NEGATIVE_X;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE_CUBE_MAP_POSITIVE_Y;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE_CUBE_MAP_NEGATIVE_Y;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE_CUBE_MAP_POSITIVE_Z;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE_CUBE_MAP_NEGATIVE_Z;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.MAX_CUBE_MAP_TEXTURE_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE0;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE1;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE2;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE3;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE4;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE5;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE6;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE7;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE8;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE9;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE10;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE11;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE12;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE13;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE14;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE15;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE16;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE17;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE18;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE19;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE20;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE21;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE22;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE23;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE24;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE25;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE26;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE27;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE28;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE29;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE30;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.TEXTURE31;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.ACTIVE_TEXTURE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.REPEAT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.CLAMP_TO_EDGE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.MIRRORED_REPEAT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FLOAT_VEC2;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FLOAT_VEC3;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FLOAT_VEC4;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.INT_VEC2;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.INT_VEC3;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.INT_VEC4;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BOOL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BOOL_VEC2;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BOOL_VEC3;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BOOL_VEC4;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FLOAT_MAT2;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FLOAT_MAT3;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FLOAT_MAT4;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.SAMPLER_2D;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.SAMPLER_CUBE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.VERTEX_ATTRIB_ARRAY_ENABLED;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.VERTEX_ATTRIB_ARRAY_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.VERTEX_ATTRIB_ARRAY_STRIDE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.VERTEX_ATTRIB_ARRAY_TYPE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.VERTEX_ATTRIB_ARRAY_NORMALIZED;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.VERTEX_ATTRIB_ARRAY_POINTER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.VERTEX_ATTRIB_ARRAY_BUFFER_BINDING;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.COMPILE_STATUS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.LOW_FLOAT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.MEDIUM_FLOAT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.HIGH_FLOAT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.LOW_INT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.MEDIUM_INT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.HIGH_INT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FRAMEBUFFER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.RENDERBUFFER;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.RGBA4;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.RGB5_A1;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.RGB565;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DEPTH_COMPONENT16;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_INDEX;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_INDEX8;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DEPTH_STENCIL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.RENDERBUFFER_WIDTH;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.RENDERBUFFER_HEIGHT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.RENDERBUFFER_INTERNAL_FORMAT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.RENDERBUFFER_RED_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.RENDERBUFFER_GREEN_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.RENDERBUFFER_BLUE_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.RENDERBUFFER_ALPHA_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.RENDERBUFFER_DEPTH_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.RENDERBUFFER_STENCIL_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FRAMEBUFFER_ATTACHMENT_OBJECT_NAME;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FRAMEBUFFER_ATTACHMENT_TEXTURE_CUBE_MAP_FACE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.COLOR_ATTACHMENT0;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DEPTH_ATTACHMENT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.STENCIL_ATTACHMENT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.DEPTH_STENCIL_ATTACHMENT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.NONE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FRAMEBUFFER_COMPLETE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FRAMEBUFFER_INCOMPLETE_DIMENSIONS;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FRAMEBUFFER_UNSUPPORTED;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.FRAMEBUFFER_BINDING;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.RENDERBUFFER_BINDING;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.MAX_RENDERBUFFER_SIZE;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.INVALID_FRAMEBUFFER_OPERATION;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.UNPACK_FLIP_Y_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.UNPACK_PREMULTIPLY_ALPHA_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.CONTEXT_LOST_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.UNPACK_COLORSPACE_CONVERSION_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WebGLRenderingContext.prototype.BROWSER_DEFAULT_WEBGL;
 
 
@@ -2483,7 +2488,7 @@ WebGLRenderingContext.prototype.linkProgram = function(program) {};
 
 /**
  * @param {number} pname
- * @param {number} param
+ * @param {number|boolean} param
  * @return {undefined}
  */
 WebGLRenderingContext.prototype.pixelStorei = function(pname, param) {};
@@ -2596,8 +2601,7 @@ WebGLRenderingContext.prototype.stencilOpSeparate = function(
  * @param {number} internalformat
  * @param {number} format or width
  * @param {number} type or height
- * @param {ImageData|HTMLImageElement|HTMLCanvasElement|HTMLVideoElement|
- *     number} img or border
+ * @param {?TexImageSource|number} img or border
  * @param {number=} opt_format
  * @param {number=} opt_type
  * @param {ArrayBufferView=} opt_pixels
@@ -2632,8 +2636,7 @@ WebGLRenderingContext.prototype.texParameteri = function(
  * @param {number} yoffset
  * @param {number} format or width
  * @param {number} type or height
- * @param {ImageData|HTMLImageElement|HTMLCanvasElement|HTMLVideoElement|
- *     number} data or format
+ * @param {?TexImageSource|number} data or format
  * @param {number=} opt_type
  * @param {ArrayBufferView=} opt_pixels
  * @return {undefined}
@@ -2901,7 +2904,6 @@ WebGLRenderingContext.prototype.viewport = function(x, y, width, height) {};
 
 /**
  * @constructor
- * @noalias
  */
 function WebGLContextAttributes() {}
 
@@ -2938,17 +2940,22 @@ WebGLContextAttributes.prototype.preserveDrawingBuffer;
 /**
  * @type {boolean}
  */
-WebGLContextAttributes.prototype.preferLowPowerToHighPerformance;
+WebGLContextAttributes.prototype.desynchronized;
 
 /**
  * @type {boolean}
  */
 WebGLContextAttributes.prototype.failIfMajorPerformanceCaveat;
 
+/**
+ * Possible values: 'default', 'low-power', 'high-performance'
+ * @type {string}
+ */
+WebGLContextAttributes.prototype.powerPreference;
+
 /**
  * @param {string} eventType
  * @constructor
- * @noalias
  * @extends {Event}
  */
 function WebGLContextEvent(eventType) {}
@@ -2961,7 +2968,6 @@ WebGLContextEvent.prototype.statusMessage;
 
 /**
  * @constructor
- * @noalias
  */
 function WebGLShaderPrecisionFormat() {}
 
@@ -2983,14 +2989,12 @@ WebGLShaderPrecisionFormat.prototype.precision;
 
 /**
  * @constructor
- * @noalias
  */
 function WebGLObject() {}
 
 
 /**
  * @constructor
- * @noalias
  * @extends {WebGLObject}
  */
 function WebGLBuffer() {}
@@ -2998,7 +3002,6 @@ function WebGLBuffer() {}
 
 /**
  * @constructor
- * @noalias
  * @extends {WebGLObject}
  */
 function WebGLFramebuffer() {}
@@ -3006,7 +3009,6 @@ function WebGLFramebuffer() {}
 
 /**
  * @constructor
- * @noalias
  * @extends {WebGLObject}
  */
 function WebGLProgram() {}
@@ -3014,7 +3016,6 @@ function WebGLProgram() {}
 
 /**
  * @constructor
- * @noalias
  * @extends {WebGLObject}
  */
 function WebGLRenderbuffer() {}
@@ -3022,7 +3023,6 @@ function WebGLRenderbuffer() {}
 
 /**
  * @constructor
- * @noalias
  * @extends {WebGLObject}
  */
 function WebGLShader() {}
@@ -3030,7 +3030,6 @@ function WebGLShader() {}
 
 /**
  * @constructor
- * @noalias
  * @extends {WebGLObject}
  */
 function WebGLTexture() {}
@@ -3038,7 +3037,6 @@ function WebGLTexture() {}
 
 /**
  * @constructor
- * @noalias
  */
 function WebGLActiveInfo() {}
 
@@ -3054,7 +3052,6 @@ WebGLActiveInfo.prototype.name;
 
 /**
  * @constructor
- * @noalias
  */
 function WebGLUniformLocation() {}
 
@@ -3062,7 +3059,6 @@ function WebGLUniformLocation() {}
 /**
  * @see http://www.khronos.org/registry/webgl/extensions/OES_texture_float/
  * @constructor
- * @noalias
  */
 function OES_texture_float() {}
 
@@ -3070,7 +3066,6 @@ function OES_texture_float() {}
 /**
  * @see http://www.khronos.org/registry/webgl/extensions/OES_texture_half_float/
  * @constructor
- * @noalias
  */
 function OES_texture_half_float() {}
 
@@ -3081,7 +3076,6 @@ OES_texture_half_float.prototype.HALF_FLOAT_OES;
 /**
  * @see http://www.khronos.org/registry/webgl/extensions/WEBGL_lose_context/
  * @constructor
- * @noalias
  */
 function WEBGL_lose_context() {}
 
@@ -3093,7 +3087,6 @@ WEBGL_lose_context.prototype.restoreContext = function() {};
 /**
  * @see http://www.khronos.org/registry/webgl/extensions/OES_standard_derivatives/
  * @constructor
- * @noalias
  */
 function OES_standard_derivatives() {}
 
@@ -3104,7 +3097,6 @@ OES_standard_derivatives.prototype.FRAGMENT_SHADER_DERIVATIVE_HINT_OES;
 /**
  * @see http://www.khronos.org/registry/webgl/extensions/OES_vertex_array_object/
  * @constructor
- * @noalias
  * @extends {WebGLObject}
  */
 function WebGLVertexArrayObjectOES() {}
@@ -3113,7 +3105,6 @@ function WebGLVertexArrayObjectOES() {}
 /**
  * @see http://www.khronos.org/registry/webgl/extensions/OES_vertex_array_object/
  * @constructor
- * @noalias
  */
 function OES_vertex_array_object() {}
 
@@ -3150,21 +3141,19 @@ OES_vertex_array_object.prototype.bindVertexArrayOES = function(arrayObject) {};
 /**
  * @see http://www.khronos.org/registry/webgl/extensions/WEBGL_debug_renderer_info/
  * @constructor
- * @noalias
  */
 function WEBGL_debug_renderer_info() {}
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_debug_renderer_info.prototype.UNMASKED_VENDOR_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_debug_renderer_info.prototype.UNMASKED_RENDERER_WEBGL;
 
 
 /**
  * @see http://www.khronos.org/registry/webgl/extensions/WEBGL_debug_shaders/
  * @constructor
- * @noalias
  */
 function WEBGL_debug_shaders() {}
 
@@ -3179,27 +3168,25 @@ WEBGL_debug_shaders.prototype.getTranslatedShaderSource = function(shader) {};
 /**
  * @see http://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_s3tc/
  * @constructor
- * @noalias
  */
 function WEBGL_compressed_texture_s3tc() {}
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_compressed_texture_s3tc.prototype.COMPRESSED_RGB_S3TC_DXT1_EXT;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_compressed_texture_s3tc.prototype.COMPRESSED_RGBA_S3TC_DXT1_EXT;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_compressed_texture_s3tc.prototype.COMPRESSED_RGBA_S3TC_DXT3_EXT;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_compressed_texture_s3tc.prototype.COMPRESSED_RGBA_S3TC_DXT5_EXT;
 
 
 /**
  * @see http://www.khronos.org/registry/webgl/extensions/OES_depth_texture/
  * @constructor
- * @noalias
  */
 function OES_depth_texture() {}
 
@@ -3207,7 +3194,6 @@ function OES_depth_texture() {}
 /**
  * @see http://www.khronos.org/registry/webgl/extensions/OES_element_index_uint/
  * @constructor
- * @noalias
  */
 function OES_element_index_uint() {}
 
@@ -3215,124 +3201,122 @@ function OES_element_index_uint() {}
 /**
  * @see http://www.khronos.org/registry/webgl/extensions/EXT_texture_filter_anisotropic/
  * @constructor
- * @noalias
  */
 function EXT_texture_filter_anisotropic() {}
 
-/** @type {number} */
+/** @const {number} */
 EXT_texture_filter_anisotropic.prototype.TEXTURE_MAX_ANISOTROPY_EXT;
 
-/** @type {number} */
+/** @const {number} */
 EXT_texture_filter_anisotropic.prototype.MAX_TEXTURE_MAX_ANISOTROPY_EXT;
 
 
 /**
  * @see https://www.khronos.org/registry/webgl/extensions/WEBGL_draw_buffers/
  * @constructor
- * @noalias
  */
 function WEBGL_draw_buffers() {}
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.COLOR_ATTACHMENT0_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.COLOR_ATTACHMENT1_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.COLOR_ATTACHMENT2_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.COLOR_ATTACHMENT3_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.COLOR_ATTACHMENT4_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.COLOR_ATTACHMENT5_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.COLOR_ATTACHMENT6_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.COLOR_ATTACHMENT7_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.COLOR_ATTACHMENT8_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.COLOR_ATTACHMENT9_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.COLOR_ATTACHMENT10_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.COLOR_ATTACHMENT11_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.COLOR_ATTACHMENT12_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.COLOR_ATTACHMENT13_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.COLOR_ATTACHMENT14_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.COLOR_ATTACHMENT15_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.DRAW_BUFFER0_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.DRAW_BUFFER1_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.DRAW_BUFFER2_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.DRAW_BUFFER3_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.DRAW_BUFFER4_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.DRAW_BUFFER5_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.DRAW_BUFFER6_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.DRAW_BUFFER7_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.DRAW_BUFFER8_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.DRAW_BUFFER9_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.DRAW_BUFFER10_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.DRAW_BUFFER11_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.DRAW_BUFFER12_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.DRAW_BUFFER13_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.DRAW_BUFFER14_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.DRAW_BUFFER15_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.MAX_COLOR_ATTACHMENTS_WEBGL;
 
-/** @type {number} */
+/** @const {number} */
 WEBGL_draw_buffers.prototype.MAX_DRAW_BUFFERS_WEBGL;
 
 /**
@@ -3345,12 +3329,11 @@ WEBGL_draw_buffers.prototype.drawBuffersWEBGL = function(buffers) {};
 /**
  * @see http://www.khronos.org/registry/webgl/extensions/ANGLE_instanced_arrays/
  * @constructor
- * @noalias
  */
 function ANGLE_instanced_arrays() {}
 
 
-/** @type {number} */
+/** @const {number} */
 ANGLE_instanced_arrays.prototype.VERTEX_ATTRIB_ARRAY_DIVISOR_ANGLE;
 
 
diff --git a/javascript/externs/web/webkit_dom.js b/javascript/externs/web/webkit_dom.js
index 7e4717ecfcd5..2ac3f9d2f96c 100644
--- a/javascript/externs/web/webkit_dom.js
+++ b/javascript/externs/web/webkit_dom.js
@@ -22,7 +22,6 @@
  * @externs
  */
 
-
 /**
  * @param {boolean=} opt_center
  * @see https://bugzilla.mozilla.org/show_bug.cgi?id=403510
@@ -30,22 +29,6 @@
  */
 Element.prototype.scrollIntoViewIfNeeded = function(opt_center) {};
 
-/**
- * @constructor
- * @see http://trac.webkit.org/browser/trunk/Source/WebCore/page/MemoryInfo.idl
- * @see http://trac.webkit.org/browser/trunk/Source/WebCore/page/MemoryInfo.cpp
- */
-function MemoryInfo() {};
-
-/** @type {number} */
-MemoryInfo.prototype.totalJSHeapSize;
-
-/** @type {number} */
-MemoryInfo.prototype.usedJSHeapSize;
-
-/** @type {number} */
-MemoryInfo.prototype.jsHeapSizeLimit;
-
 /**
  * @constructor
  * @see http://trac.webkit.org/browser/trunk/Source/WebCore/inspector/ScriptProfileNode.idl
@@ -94,202 +77,12 @@ ScriptProfile.prototype.uid;
 /** @type {ScriptProfileNode} */
 ScriptProfile.prototype.head;
 
-/**
- * @constructor
- * @see http://trac.webkit.org/browser/trunk/Source/WebCore/page/Console.idl
- * @see http://trac.webkit.org/browser/trunk/Source/WebCore/page/Console.cpp
- */
-function Console() {};
-
-/**
- * @param {*} condition
- * @param {...*} var_args
- * @return {undefined}
- */
-Console.prototype.assert = function(condition, var_args) {};
-
-/**
- * @param {...*} var_args
- * @return {undefined}
- */
-Console.prototype.error = function(var_args) {};
-
-/**
- * @param {...*} var_args
- * @return {undefined}
- */
-Console.prototype.info = function(var_args) {};
-
-/**
- * @param {...*} var_args
- * @return {undefined}
- */
-Console.prototype.log = function(var_args) {};
-
-/**
- * @param {...*} var_args
- * @return {undefined}
- */
-Console.prototype.warn = function(var_args) {};
-
-/**
- * @param {...*} var_args
- * @return {undefined}
- */
-Console.prototype.debug = function(var_args) {};
-
-/**
- * @param {*} value
- * @return {undefined}
- */
-Console.prototype.dir = function(value) {};
-
-/**
- * @param {...*} var_args
- * @return {undefined}
- */
-Console.prototype.dirxml = function(var_args) {};
-
-/**
- * @param {!Object} data
- * @param {*=} opt_columns
- * @return {undefined}
- */
-Console.prototype.table = function(data, opt_columns) {};
-
-/**
- * @param {...*} var_args
- * @return {undefined}
- */
-Console.prototype.trace = function(var_args) {};
-
-/**
- * @param {*} value
- * @return {undefined}
- */
-Console.prototype.count = function(value) {};
-
-/**
- * @param {*} value
- * @return {undefined}
- */
-Console.prototype.markTimeline = function(value) {};
-
-/**
- * @param {string=} opt_title
- * @return {undefined}
- */
-Console.prototype.profile = function(opt_title) {};
-
-/** @type {Array<ScriptProfile>} */
-Console.prototype.profiles;
-
-/**
- * @param {string=} opt_title
- * @return {undefined}
- */
-Console.prototype.profileEnd = function(opt_title) {};
-
-/**
- * @param {string} name
- * @return {undefined}
- */
-Console.prototype.time = function(name) {};
-
-/**
- * @param {string} name
- * @return {undefined}
- */
-Console.prototype.timeEnd = function(name) {};
-
-/**
- * @param {*} value
- * @return {undefined}
- */
-Console.prototype.timeStamp = function(value) {};
-
-/**
- * @param {...*} var_args
- * @return {undefined}
- */
-Console.prototype.group = function(var_args) {};
-
-/**
- * @param {...*} var_args
- * @return {undefined}
- */
-Console.prototype.groupCollapsed = function(var_args) {};
-
-Console.prototype.groupEnd = function() {};
-
-Console.prototype.clear = function() {};
-
-/** @type {MemoryInfo} */
-Console.prototype.memory;
-
-/** @type {!Console} */
-Window.prototype.console;
-
-/**
- * @type {!Console}
- * @suppress {duplicate}
- */
-var console;
-
 /**
  * @type {number}
  * @see http://developer.android.com/reference/android/webkit/WebView.html
  */
 Window.prototype.devicePixelRatio;
 
-/** @type {Node} */
-Selection.prototype.baseNode;
-
-/** @type {number} */
-Selection.prototype.baseOffset;
-
-/** @type {Node} */
-Selection.prototype.extentNode;
-
-/** @type {number} */
-Selection.prototype.extentOffset;
-
-/** @type {string} */
-Selection.prototype.type;
-
-/**
- * @return {undefined}
- */
-Selection.prototype.empty = function() {};
-
-/**
- * @param {Node} baseNode
- * @param {number} baseOffset
- * @param {Node} extentNode
- * @param {number} extentOffset
- * @return {undefined}
- */
-Selection.prototype.setBaseAndExtent =
- function(baseNode, baseOffset, extentNode, extentOffset) {};
-
-/**
- * @param {string} alter
- * @param {string} direction
- * @param {string} granularity
- * @return {undefined}
- */
-Selection.prototype.modify = function(alter, direction, granularity) {};
-
-/**
- * @param {Element} element
- * @param {string} pseudoElement
- * @param {boolean=} opt_authorOnly
- * @return {CSSRuleList}
- * @nosideeffects
- */
-ViewCSS.prototype.getMatchedCSSRules =
-    function(element, pseudoElement, opt_authorOnly) {};
-
 /**
  * @param {string} contextId
  * @param {string} name
@@ -309,3 +102,17 @@ Document.prototype.getCSSCanvasContext =
  * @see https://developer.mozilla.org/en-US/docs/Web/API/Document/caretRangeFromPoint
  */
 Document.prototype.caretRangeFromPoint = function(x, y) {};
+
+/**
+ * @return {!Promise<boolean>}
+ * @nosideeffects
+ * @see https://webkit.org/blog/8124/introducing-storage-access-api
+ */
+Document.prototype.hasStorageAccess = function() {};
+
+/**
+ * @return {!Promise<void>}
+ * @see https://webkit.org/blog/8124/introducing-storage-access-api
+ * @see https://developer.mozilla.org/docs/Web/API/Document/requestStorageAccess#Syntax
+ */
+Document.prototype.requestStorageAccess = function() {};
diff --git a/javascript/externs/web/webkit_event.js b/javascript/externs/web/webkit_event.js
index 9fad616f3b73..ff27f52d3e20 100644
--- a/javascript/externs/web/webkit_event.js
+++ b/javascript/externs/web/webkit_event.js
@@ -36,13 +36,11 @@ Event.prototype.wheelDeltaY;
 function WebKitAnimationEvent() {}
 
 /**
- * @type {string}
- * @const
+ * @const {string}
  */
 WebKitAnimationEvent.prototype.animationName;
 
 /**
- * @type {number}
- * @const
+ * @const {number}
  */
-WebKitAnimationEvent.prototype.elapsedTime;
\ No newline at end of file
+WebKitAnimationEvent.prototype.elapsedTime;
diff --git a/javascript/externs/web/webkit_notifications.js b/javascript/externs/web/webkit_notifications.js
index 37a01069b1fa..988101910189 100644
--- a/javascript/externs/web/webkit_notifications.js
+++ b/javascript/externs/web/webkit_notifications.js
@@ -19,12 +19,26 @@
  */
 
 /**
- * @typedef {{dir: (string|undefined), lang: (string|undefined),
- *            body: (string|undefined), tag: (string|undefined),
- *            icon: (string|undefined),
- *            requireInteraction: (boolean|undefined),
- *            actions: (!Array<!NotificationAction>|undefined)}}
- * @see http://notifications.spec.whatwg.org/#notificationoptions
+ * @typedef {{
+ *     dir: (string|undefined),
+ *     lang: (string|undefined),
+ *     body: (string|undefined),
+ *     tag: (string|undefined),
+ *     image: (string|undefined),
+ *     icon: (string|undefined),
+ *     badge: (string|undefined),
+ *     vibrate: (!Array<number>|undefined),
+ *     timestamp: (number|undefined),
+ *     renotify: (boolean|undefined),
+ *     silent: (boolean|undefined),
+ *     requireInteraction: (boolean|undefined),
+ *     data: (*|undefined),
+ *     actions: (!Array<!NotificationAction>|undefined),
+ * }}
+ * TODO(user): change the type of data to a serializable object
+ * (https://html.spec.whatwg.org/multipage/structured-data.html).
+ *
+ * @see http://notifications.spec.whatwg.org/#notification
  */
 var NotificationOptions;
 
@@ -70,26 +84,15 @@ Notification.permission;
  */
 Notification.requestPermission = function(opt_callback) {};
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-Notification.prototype.addEventListener =
-    function(type, listener, opt_useCapture) {};
+/** @override */
+Notification.prototype.addEventListener = function(
+    type, listener, opt_options) {};
 
-/**
- * @param {boolean=} opt_useCapture
- * @override
- * @return {undefined}
- */
-Notification.prototype.removeEventListener =
-    function(type, listener, opt_useCapture) {};
+/** @override */
+Notification.prototype.removeEventListener = function(
+    type, listener, opt_options) {};
 
-/**
- * @override
- * @return {boolean}
- */
+/** @override */
 Notification.prototype.dispatchEvent = function(evt) {};
 
 /**
@@ -121,6 +124,11 @@ Notification.prototype.tag;
  */
 Notification.prototype.replaceId;
 
+/**
+ * @type {*}
+ */
+Notification.prototype.data;
+
 /**
  * The string used by clients to specify the directionality (rtl/ltr) of the
  * notification.
@@ -243,5 +251,8 @@ Window.prototype.webkitNotifications;
  */
 function NotificationEvent(type, opt_eventInitDict) {}
 
-/** @type {?Notification} */
+/** @type {!Notification} */
 NotificationEvent.prototype.notification;
+
+/** @type {string} */
+NotificationEvent.prototype.action;
diff --git a/javascript/externs/web/webkit_usercontent.js b/javascript/externs/web/webkit_usercontent.js
index 4b28bf69c662..3decf2899d33 100644
--- a/javascript/externs/web/webkit_usercontent.js
+++ b/javascript/externs/web/webkit_usercontent.js
@@ -50,7 +50,6 @@ UserMessageHandler.prototype.postMessage = function(message) {};
 
 
 /**
- * @type {!WebKitNamespace}
- * @const
+ * @const {!WebKitNamespace}
  */
 var webkit;
diff --git a/javascript/externs/web/webstorage.js b/javascript/externs/web/webstorage.js
index eee69d258145..796ff61989f4 100644
--- a/javascript/externs/web/webstorage.js
+++ b/javascript/externs/web/webstorage.js
@@ -15,19 +15,18 @@
  */
 /**
  * @fileoverview Definitions for W3C's WebStorage specification.
- * This file depends on html5.js.
+ * This file depends on w3c_dom1.js and w3c_event.js.
  * @externs
  */
 
 /**
  * @interface
- * @see http://www.w3.org/TR/2011/CR-webstorage-20111208/#the-storage-interface
+ * @see https://www.w3.org/TR/webstorage/#the-storage-interface
  */
 function Storage() {}
 
 /**
- * @type {number}
- * @const
+ * @const {number}
  */
 Storage.prototype.length;
 
@@ -63,47 +62,71 @@ Storage.prototype.clear = function() {};
 
 /**
  * @interface
- * @see http://www.w3.org/TR/2011/CR-webstorage-20111208/#the-sessionstorage-attribute
+ * @see https://www.w3.org/TR/webstorage/#the-sessionstorage-attribute
  */
 function WindowSessionStorage() {}
 
 /**
- * @type {Storage}
+ * @type {!Storage}
  */
 WindowSessionStorage.prototype.sessionStorage;
 
 /**
  * Window implements WindowSessionStorage
  *
- * @type {Storage}
+ * @type {!Storage}
  */
 Window.prototype.sessionStorage;
 
 /**
  * @interface
- * @see http://www.w3.org/TR/2011/CR-webstorage-20111208/#the-localstorage-attribute
+ * @see https://www.w3.org/TR/webstorage/#the-localstorage-attribute
  */
 function WindowLocalStorage() {}
 
 /**
- * @type {Storage}
+ * @type {!Storage}
  */
 WindowLocalStorage.prototype.localStorage;
 
 /**
  * Window implements WindowLocalStorage
  *
- * @type {Storage}
+ * @type {!Storage}
  */
 Window.prototype.localStorage;
 
+/**
+ * @record
+ * @extends {EventInit}
+ * @see https://www.w3.org/TR/webstorage/#the-storageevent-interface
+ */
+function StorageEventInit() {}
+
+/** @type {undefined|string} */
+StorageEventInit.prototype.key;
+
+/** @type {undefined|string} */
+StorageEventInit.prototype.oldValue;
+
+/** @type {undefined|string} */
+StorageEventInit.prototype.newValue;
+
+/** @type {string} */
+StorageEventInit.prototype.url;
+
+/** @type {undefined|!Storage} */
+StorageEventInit.prototype.storageArea;
+
 /**
  * This is the storage event interface.
- * @see http://www.w3.org/TR/2011/CR-webstorage-20111208/#the-storage-event
+ * @see https://www.w3.org/TR/webstorage/#the-storage-event
  * @extends {Event}
+ * @param {string} type
+ * @param {!StorageEventInit=} eventInitDict
  * @constructor
  */
-function StorageEvent() {}
+function StorageEvent(type, eventInitDict) {}
 
 /**
  * @type {string}
diff --git a/javascript/externs/web/whatwg_encoding.js b/javascript/externs/web/whatwg_encoding.js
index a5d8eca19675..7d55bdd9fdfb 100644
--- a/javascript/externs/web/whatwg_encoding.js
+++ b/javascript/externs/web/whatwg_encoding.js
@@ -34,7 +34,7 @@ function TextDecoder(encoding, options) {}
 /**
  * @param {!BufferSource=} input
  * @param {?Object=} options
- * @return {!string}
+ * @return {string}
  * @see https://encoding.spec.whatwg.org/#textdecoder
  */
 TextDecoder.prototype.decode = function decode(input, options) {};
@@ -52,3 +52,10 @@ function TextEncoder(utfLabel) {}
  * @return {!Uint8Array}
  */
 TextEncoder.prototype.encode = function(input) {};
+
+/**
+ * @param {string} input
+ * @param {!Uint8Array} uint8Array
+ * @return {{read: number, written: number}}
+ */
+TextEncoder.prototype.encodeInto = function(input, uint8Array) {};
diff --git a/javascript/externs/web/window.js b/javascript/externs/web/window.js
index 83b860866da6..f6b73546840a 100644
--- a/javascript/externs/web/window.js
+++ b/javascript/externs/web/window.js
@@ -30,92 +30,61 @@
  * @see https://developer.mozilla.org/en/DOM/window.top
  * @const
  */
-var top;
-
-/**
- * @type {!Navigator}
- * @see https://developer.mozilla.org/en/DOM/window.navigator
- * @const
- */
-var navigator;
-
-/**
- * @type {!HTMLDocument}
- * @see https://developer.mozilla.org/en/DOM/window.document
- * @const
- */
-var document;
-
-/**
- * @type {!Location}
- * @see https://developer.mozilla.org/en/DOM/window.location
- * @const
- * @suppress {duplicate}
- * @implicitCast
- */
-var location;
-
-/**
- * @type {!Screen}
- * @see https://developer.mozilla.org/En/DOM/window.screen
- * @const
- */
-var screen;
-
+ var top;
+
+ /**
+  * @type {!Navigator}
+  * @see https://developer.mozilla.org/en/DOM/window.navigator
+  * @const
+  */
+ var navigator;
+ 
+ /**
+  * @type {!HTMLDocument}
+  * @see https://developer.mozilla.org/en/DOM/window.document
+  * @const
+  */
+ var document;
+ 
+ /**
+  * @type {!Location}
+  * @see https://developer.mozilla.org/en/DOM/window.location
+  * @const
+  * @suppress {duplicate}
+  * @implicitCast
+  */
+ var location;
+ 
+ /**
+  * @type {!Screen}
+  * @see https://developer.mozilla.org/En/DOM/window.screen
+  * @const
+  */
+ var screen;
+ 
+ /**
+  * @type {!Window}
+  * @see https://developer.mozilla.org/En/DOM/Window.self
+  * @const
+  */
+ var self;
 /**
  * @type {!Window}
- * @see https://developer.mozilla.org/En/DOM/Window.self
- * @const
- */
-var self;
-
-// Magic functions for Firefox's LiveConnect.
-// We'll probably never use these in practice. But redefining them
-// will fire up the JVM, so we want to reserve the symbol names.
-
-/**
- * @see https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/JavaArray
- */
-var JavaArray;
-
-/**
- * @see https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/JavaClass
- */
-var JavaClass;
-
-// We just ripped this from the FF source; it doesn't appear to be
-// publicly documented.
-var JavaMember;
-
-/**
- * @see https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/JavaObject
- */
-var JavaObject;
-
-/**
- * @see https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/JavaPackage
+ * @see https://developer.mozilla.org/en/DOM/window
  */
-var JavaPackage;
+var window;
 
 /**
- * @see https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/Packages
+ * @const {boolean}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/Window/isSecureContext
  */
-var Packages;
+var isSecureContext;
 
 /**
- * @see https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/java
+ * @const {!VisualViewport}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/Window/visualViewport
  */
-var java;
-
-/**
- * @see https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/netscape
- */
-var netscape;
-
-/**
- * @see https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/sun
- */
-var sun;
+var visualViewport;
 
 /**
  * @param {*} message
@@ -125,7 +94,7 @@ var sun;
 function alert(message) {}
 
 /**
- * @param {number|undefined|null} immediateID
+ * @param {number=} immediateID
  * @see https://developer.mozilla.org/en-US/docs/DOM/window.clearImmediate
  * @see http://msdn.microsoft.com/en-us/library/ie/hh924825(v=vs.85).aspx
  * @return {undefined}
@@ -133,7 +102,7 @@ function alert(message) {}
 function clearImmediate(immediateID) {}
 
 /**
- * @param {number|undefined?} intervalID
+ * @param {?number|undefined} intervalID
  * @see https://developer.mozilla.org/en/DOM/window.clearInterval
  * @suppress {duplicate}
  * @return {undefined}
@@ -141,7 +110,7 @@ function clearImmediate(immediateID) {}
 function clearInterval(intervalID) {}
 
 /**
- * @param {number|undefined?} timeoutID
+ * @param {?number|undefined} timeoutID
  * @see https://developer.mozilla.org/en/DOM/window.clearTimeout
  * @suppress {duplicate}
  * @return {undefined}
@@ -172,30 +141,32 @@ function prompt(message, opt_value) {}
 
 /**
  * @param {function()} callback
+ * @param {...?} callbackParams
  * @return {number}
  * @see https://developer.mozilla.org/en-US/docs/DOM/window.setImmediate
  * @see http://msdn.microsoft.com/en-us/library/ie/hh773176(v=vs.85).aspx
  */
-function setImmediate(callback) {}
+function setImmediate(callback, callbackParams) {}
 
 /**
- * @param {Function|string} callback
+ * @param {Function|!TrustedScript|string} callback
  * @param {number=} opt_delay
+ * @param {...?} callbackParams
  * @return {number}
  * @see https://developer.mozilla.org/en/DOM/window.setInterval
  * @see https://html.spec.whatwg.org/multipage/webappapis.html#timers
  */
-function setInterval(callback, opt_delay) {}
+function setInterval(callback, opt_delay, callbackParams) {}
 
 /**
- * @param {Function|string} callback
+ * @param {Function|!TrustedScript|string} callback
  * @param {number=} opt_delay
- * @param {...*} var_args
+ * @param {...*} callbackParams
  * @return {number}
  * @see https://developer.mozilla.org/en/DOM/window.setTimeout
  * @see https://html.spec.whatwg.org/multipage/webappapis.html#timers
  */
-function setTimeout(callback, opt_delay, var_args) {}
+function setTimeout(callback, opt_delay, callbackParams) {}
 
 /**
  * Returns whether the object has a property with the specified name.
@@ -206,3 +177,11 @@ function setTimeout(callback, opt_delay, var_args) {}
  * @see http://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/hasOwnProperty
  */
 function hasOwnProperty (propertyName) {}
+
+/**
+ * @param {function()} callback
+ * @return {undefined}
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/queueMicrotask
+ * @see https://html.spec.whatwg.org/multipage/timers-and-user-prompts.html#microtask-queuing
+ */
+function queueMicrotask(callback) {}