Add @Native(...) annotation for native class names.

tests/compiler/dart2js/mock_libraries.dart

 // Copyright (c) 2014, 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 for creating mock versions of platform and internal libraries.
 
 library mock_libraries;
 
 String buildLibrarySource(
     Map<String, String> elementMap,
@@ skipping 134 matching lines @@
   'isJsIndexable': 'isJsIndexable(a, b) {}',
   'JavaScriptIndexingBehavior': 'abstract class JavaScriptIndexingBehavior {}',
   'JSInvocationMirror': 'class JSInvocationMirror {}',
   'listSuperNativeTypeCast': 'listSuperNativeTypeCast(value) {}',
   'listSuperNativeTypeCheck': 'listSuperNativeTypeCheck(value) {}',
   'listSuperTypeCast': 'listSuperTypeCast(value) {}',
   'listSuperTypeCheck': 'listSuperTypeCheck(value) {}',
   'listTypeCast': 'listTypeCast(value) {}',
   'listTypeCheck': 'listTypeCheck(value) {}',
   'makeLiteralMap': 'makeLiteralMap(List keyValuePairs) {}',
+  'Native': 'class Native {}',
   'NoInline': 'class NoInline {}',
   'NoSideEffects': 'class NoSideEffects {}',
   'NoThrows': 'class NoThrows {}',
   'numberOrStringSuperNativeTypeCast':
       'numberOrStringSuperNativeTypeCast(value) {}',
   'numberOrStringSuperNativeTypeCheck':
       'numberOrStringSuperNativeTypeCheck(value) {}',
   'numberOrStringSuperTypeCast': 'numberOrStringSuperTypeCast(value) {}',
   'numberOrStringSuperTypeCheck': 'numberOrStringSuperTypeCheck(value) {}',
   'numTypeCast': 'numTypeCast(value) {}',
@@ skipping 163 matching lines @@
   '_callInIsolate': 'var _callInIsolate;',
   '_WorkerBase': 'class _WorkerBase {}',
 };
 
 const Map<String, String> DEFAULT_MIRRORS_LIBRARY = const <String, String>{
   'Comment': 'class Comment {}',
   'MirrorSystem': 'class MirrorSystem {}',
   'MirrorsUsed': 'class MirrorsUsed {}',
 };