Update tests using .isCompatibilityMode to understand .featureLevel

And update all comments about removing `compatibilityMode: boolean`.

src/common/runtime/cmdline.ts

@@ -121,7 +121,7 @@ for (let i = 0; i < sys.args.length; ++i) {
 let codeCoverage: CodeCoverageProvider | undefined = undefined;
 
 if (globalTestConfig.compatibility || globalTestConfig.forceFallbackAdapter) {
-  // MAINTENANCE_TODO: remove the cast once compatibilityMode is officially added
+  // MAINTENANCE_TODO: remove compatibilityMode (and the typecast) once no longer needed.
   setDefaultRequestAdapterOptions({
     compatibilityMode: globalTestConfig.compatibility,
     featureLevel: globalTestConfig.compatibility ? 'compatibility' : 'core',

src/common/runtime/helper/utils_worker.ts

@@ -26,7 +26,7 @@ export function setupWorkerEnvironment(ctsOptions: CTSOptions): Logger {
   if (powerPreference || compatibility) {
     setDefaultRequestAdapterOptions({
       ...(powerPreference && { powerPreference }),
-      // MAINTENANCE_TODO: Change this to whatever the option ends up being
+      // MAINTENANCE_TODO: remove compatibilityMode once no longer needed.
       ...(compatibility && { compatibilityMode: true, featureLevel: 'compatibility' }),
     });
   }

src/common/runtime/server.ts

@@ -120,7 +120,7 @@ for (let i = 0; i < sys.args.length; ++i) {
 let codeCoverage: CodeCoverageProvider | undefined = undefined;
 
 if (globalTestConfig.compatibility || globalTestConfig.forceFallbackAdapter) {
-  // MAINTENANCE_TODO: remove the cast once compatibilityMode is officially added
+  // MAINTENANCE_TODO: remove compatibilityMode (and the typecast) once no longer needed.
   setDefaultRequestAdapterOptions({
     compatibilityMode: globalTestConfig.compatibility,
     featureLevel: globalTestConfig.compatibility ? 'compatibility' : 'core',

src/common/runtime/standalone.ts

@@ -84,7 +84,7 @@ stopButtonElem.addEventListener('click', () => {
 if (powerPreference || compatibility || forceFallbackAdapter) {
   setDefaultRequestAdapterOptions({
     ...(powerPreference && { powerPreference }),
-    // MAINTENANCE_TODO: Change this to whatever the option ends up being
+    // MAINTENANCE_TODO: remove compatibilityMode once no longer needed.
     ...(compatibility && { compatibilityMode: true, featureLevel: 'compatibility' }),
     ...(forceFallbackAdapter && { forceFallbackAdapter: true }),
   });

src/webgpu/api/operation/adapter/requestDevice.spec.ts

@@ -491,7 +491,7 @@ g.test('always_returns_device')
 
     Note: This is a regression test for a Chrome bug crbug.com/349062459
     Checking that a requestDevice always return a device is checked in other tests above
-    but those tests have 'compatibilityMode: true' set for them by the API that getGPU
+    but those tests have 'featureLevel: "compatibility"' set for them by the API that getGPU
     returns when the test suite is run in compatibility mode.
 
     This test tries to force both compat and core separately so both code paths are
@@ -502,19 +502,33 @@ g.test('always_returns_device')
   .fn(async t => {
     const { compatibilityMode } = t.params;
     const gpu = getGPU(t.rec);
-    // MAINTENANCE_TODO: Remove this cast compatibilityMode is added.
-    const adapter = await gpu.requestAdapter({ compatibilityMode } as GPURequestAdapterOptions);
+    // MAINTENANCE_TODO: Remove compatibilityMode and the cast once compatibilityMode is no longer
+    // used (mainly in `setDefaultRequestAdapterOptions`).
+    const adapter = await gpu.requestAdapter({
+      compatibilityMode,
+      featureLevel: compatibilityMode ? 'compatibility' : 'core',
+    } as GPURequestAdapterOptions);
     if (adapter) {
+      const device = await t.requestDeviceTracked(adapter);
+      assert(device instanceof GPUDevice, 'requestDevice must return a device or throw');
+
       if (!compatibilityMode) {
-        // This check is to make sure something lower-level is not forcing compatibility mode
-        // MAINTENANCE_TODO: Remove this cast compatibilityMode is added.
+        // This check is to make sure something lower-level is not forcing compatibility mode.
+
+        // MAINTENANCE_TODO: Simplify this check (and typecast) once we standardize how to do this.
+        const adapterExtensions = adapter as unknown as {
+          isCompatibilityMode?: boolean;
+          featureLevel?: string;
+        };
         t.expect(
-          !(adapter as unknown as { isCompatibilityMode?: boolean }).isCompatibilityMode,
-          'must not be compatibility mode'
+          // Old version of Compat design.
+          !adapterExtensions.isCompatibilityMode &&
+            // Current version of Compat design, as of this writing.
+            adapterExtensions.featureLevel !== 'compatibility' &&
+            // An unlanded proposed change to the Compat design, but it doesn't hurt to just check.
+            !device.features.has('webgpu-core'),
+          'must not get a Compatibility adapter if not requested'
         );
       }
-      const device = await t.requestDeviceTracked(adapter);
-      t.expect(device instanceof GPUDevice, 'requestDevice must return a device or throw');
-      device.destroy();
     }
   });

src/webgpu/capability_info.ts

@@ -802,11 +802,15 @@ export function getDefaultLimits(featureLevel: FeatureLevel) {
 
 export function getDefaultLimitsForAdapter(adapter: GPUAdapter) {
   // MAINTENANCE_TODO: Remove casts when GPUAdapter IDL has isCompatibilityMode.
-  return getDefaultLimits(
-    (adapter as unknown as { isCompatibilityMode: boolean }).isCompatibilityMode
+  const adapterExtensions = adapter as unknown as {
+    isCompatibilityMode?: boolean;
+    featureLevel?: string;
+  };
+  const featureLevel =
+    adapterExtensions.featureLevel === 'compatibility' || adapterExtensions.isCompatibilityMode
       ? 'compatibility'
-      : 'core'
-  );
+      : 'core';
+  return getDefaultLimits(featureLevel);
 }
 
 const kEachStage = [