[dart2js] Add 'CONTEXT' diagnostic level option.

Metrics are using 'INFO' level diagnostics but these do not match the stated usage for INFO. This level was originally supposed to be used for contextual info about a previous warning/hint:
https://github.com/dart-lang/sdk/blob/main/pkg/compiler/lib/compiler_api.dart#L44

These is logic that is preventing these metrics from being printed when they are logged following a hint and hints are turned off:
https://github.com/dart-lang/sdk/blob/main/pkg/compiler/lib/src/source_file_provider.dart#L259.

Instead we introduce a 'CONTEXT' for those contextual info messages and use 'INFO' as its own level of logging.

Change-Id: Ie845f30dfd7d04fa9fe1d0a866e07c834dc64b32
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/297280
Reviewed-by: Sigmund Cherem <[email protected]>
Commit-Queue: Nate Biggs <[email protected]>

Author: natebiggs

pkg/compiler/lib/compiler_api.dart

@@ -35,12 +35,7 @@ class Diagnostic {
   /// Any other warning that is not covered by [WARNING].
   static const Diagnostic HINT = const Diagnostic(4, 'hint');
 
-  /// Additional information about the preceding non-info diagnostic from the
-  /// compiler.
-  ///
-  /// For example, consider a duplicated definition. The compiler first emits a
-  /// message about the duplicated definition, then emits an info message about
-  /// the location of the existing definition.
+  /// Informational message about the compiler.
   static const Diagnostic INFO = const Diagnostic(8, 'info');
 
   /// Informational messages that shouldn't be printed unless
@@ -50,6 +45,14 @@ class Diagnostic {
   /// An internal error in the compiler.
   static const Diagnostic CRASH = const Diagnostic(32, 'crash');
 
+  /// Additional information about the preceding non-info diagnostic from the
+  /// compiler.
+  ///
+  /// For example, consider a duplicated definition. The compiler first emits a
+  /// message about the duplicated definition, then emits an info message about
+  /// the location of the existing definition.
+  static const Diagnostic CONTEXT = const Diagnostic(64, 'context');
+
   /// An [int] representation of this kind. The ordinals are designed
   /// to be used as bitsets.
   final int ordinal;

pkg/compiler/lib/src/compiler.dart

@@ -879,7 +879,7 @@ class Compiler {
       List<DiagnosticMessage> infos, api.Diagnostic kind) {
     _reportDiagnosticMessage(message, kind);
     for (DiagnosticMessage info in infos) {
-      _reportDiagnosticMessage(info, api.Diagnostic.INFO);
+      _reportDiagnosticMessage(info, api.Diagnostic.CONTEXT);
     }
   }
 

pkg/compiler/lib/src/source_file_provider.dart

@@ -216,6 +216,7 @@ class FormattingDiagnosticHandler implements api.CompilerDiagnostics {
         return 'Hint: $message';
       case api.Diagnostic.CRASH:
         return 'Internal Error: $message';
+      case api.Diagnostic.CONTEXT:
       case api.Diagnostic.INFO:
       case api.Diagnostic.VERBOSE_INFO:
         return 'Info: $message';
@@ -256,6 +257,8 @@ class FormattingDiagnosticHandler implements api.CompilerDiagnostics {
     } else if (kind == api.Diagnostic.CRASH) {
       color = colors.red;
     } else if (kind == api.Diagnostic.INFO) {
+      color = colors.green;
+    } else if (kind == api.Diagnostic.CONTEXT) {
       if (lastKind == api.Diagnostic.WARNING && !showWarnings) return;
       if (lastKind == api.Diagnostic.HINT && !showHints) return;
       color = colors.green;