Add @anonymous annotation and restrict object literal constructors to only anonymous classes. This …

pkg/compiler/lib/src/js_backend/backend_helpers.dart

 // Copyright (c) 2015, 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.js_backend.helpers;
 
 import '../common.dart';
 import '../common/names.dart' show
     Uris;
 import '../common/resolution.dart' show
@@ skipping 112 matching lines @@
   Element mapLiteralUntypedMaker;
   Element mapLiteralUntypedEmptyMaker;
 
   ClassElement noSideEffectsClass;
   ClassElement noThrowsClass;
   ClassElement noInlineClass;
   ClassElement forceInlineClass;
   ClassElement irRepresentationClass;
 
   ClassElement jsAnnotationClass;
+  ClassElement jsAnonymousClass;
 
   Element getInterceptorMethod;
 
   ClassElement jsInvocationMirrorClass;
 
   ClassElement typedArrayClass;
   ClassElement typedArrayOfIntClass;
 
   /**
    * Interface used to determine if an object has the JavaScript
@@ skipping 153 matching lines @@
     } else if (uri == DART_JS_NAMES) {
       preserveNamesMarker = find(library, 'preserveNames');
     } else if (uri == DART_EMBEDDED_NAMES) {
       jsGetNameEnum = find(library, 'JsGetName');
       jsBuiltinEnum = find(library, 'JsBuiltin');
     } else if (uri == Uris.dart__native_typed_data) {
       typedArrayClass = findClass('NativeTypedArray');
       typedArrayOfIntClass = findClass('NativeTypedArrayOfInt');
     } else if (uri == PACKAGE_JS) {
       jsAnnotationClass = find(library, 'JS');
+      jsAnonymousClass = find(library, '_Anonymous');
     }
   }
 
 
   void onLibrariesLoaded(LoadedLibraries loadedLibraries) {
     assert(loadedLibraries.containsLibrary(Uris.dart_core));
     assert(loadedLibraries.containsLibrary(DART_INTERCEPTORS));
     assert(loadedLibraries.containsLibrary(DART_JS_HELPER));
 
     if (jsInvocationMirrorClass != null) {
@@ skipping 343 matching lines @@
   }
 
   Element get findIndexForNativeSubclassType {
     return findInterceptor('findIndexForNativeSubclassType');
   }
 
   Element get convertRtiToRuntimeType {
     return findHelper('convertRtiToRuntimeType');
   }
 }