Add optional message to assert in Dart2js.

pkg/compiler/lib/src/common/resolution.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart2js.common.resolution;
 
 import '../compiler.dart' show
     Compiler;
 import '../dart_types.dart' show
     DartType;
@@ skipping 24 matching lines @@
     WorldImpact impact = compiler.analyze(this, world);
     _isAnalyzed = true;
     return impact;
   }
 
   bool get isAnalyzed => _isAnalyzed;
 }
 
 /// Backend callbacks function specific to the resolution phase.
 class ResolutionCallbacks {
-  /// Register that [node] is a call to `assert`.
-  void onAssert(Send node, Registry registry) {}
+  /// Register that an assert has been seen.
+  void onAssert(Registry registry) {}
 
   /// Register that an 'await for' has been seen.
   void onAsyncForIn(AsyncForIn node, Registry registry) {}
 
   /// Called during resolution to notify to the backend that the
   /// program uses string interpolation.
   void onStringInterpolation(Registry registry) {}
 
   /// Called during resolution to notify to the backend that the
   /// program has a catch statement.
@@ skipping 51 matching lines @@
   /// Register that a super call will end up calling
   /// [: super.noSuchMethod :].
   void onSuperNoSuchMethod(Registry registry) {}
 
   /// Register that the application creates a constant map.
   void onMapLiteral(Registry registry, DartType type, bool isConstant) {}
 
   /// Called when resolving the `Symbol` constructor.
   void onSymbolConstructor(Registry registry) {}
 }