Fix for AudioContext in Frog

client/dom/frog/dom_frog.dart

 #library('dom');
 
 // Copyright (c) 2011, 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.
 
 // DO NOT EDIT
 // Auto-generated Dart DOM library.
 
 
@@ skipping 26382 matching lines @@
 // Copyright (c) 2011, 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.
 
 
 // These factory methods could all live in one factory provider class but dartc
 // has a bug (5399939) preventing that.
 
 class _AudioContextFactoryProvider {
 
-  factory AudioContext() native '''return new AudioContext();''';
+  factory AudioContext() native '''
+    var constructor = window.AudioContext || window.webkitAudioContext;
+    return new constructor();
+''';
 }
 
 class _FileReaderFactoryProvider {
 
   factory FileReader() native '''return new FileReader();''';
 }
 
 class _TypedArrayFactoryProvider {
 
   factory Float32Array(int length) => _F32(length);
@@ skipping 136 matching lines @@
       startIndex = a.length - 1;
     }
     for (int i = startIndex; i >= 0; i--) {
       if (a[i] == element) {
         return i;
       }
     }
     return -1;
   }
 }