Added constructor for AudioContext for dartc and frog

client/dom/src/_FactoryProviders.dart

 // 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() { return create(); }
+
+  static AudioContext create() native;
+}
+
 class _FileReaderFactoryProvider {
 
   factory FileReader() { return create(); }
 
   static FileReader create() native;
 }
 
 class _TypedArrayFactoryProvider {
 
   factory Float32Array(int length) => _F32(length);
@@ skipping 54 matching lines @@
 
   static WebKitPoint create(x, y) native;
 }
 
 class _XMLHttpRequestFactoryProvider {
 
   factory XMLHttpRequest() { return create(); }
 
   static XMLHttpRequest create() native;
 }