Fix sound not playing in Dartium checked mode.

tools/dom/templates/html/impl/impl_AudioContext.darttemplate

 // 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.
 
 part of web_audio;
 
 $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS {
 $!MEMBERS
 $if DART2JS
   factory AudioContext() => JS('AudioContext',
@@ skipping 16 matching lines @@
           bufferSize, numberOfInputChannels, numberOfOutputChannels);
     } else if (numberOfInputChannels != null) {
       return JS('ScriptProcessorNode', '#.call(#, #, #)', function, this,
           bufferSize, numberOfInputChannels);
     } else {
       return JS('ScriptProcessorNode', '#.call(#, #)', function, this,
           bufferSize);
     }
   }
 $endif
+
+$if DART2JS
+  @JSName('decodeAudioData')
+  @DomName('AudioContext.decodeAudioData')
+  @DocsEditable()
+  Future _decodeAudioData(ByteBuffer audioData,
+      [AudioBufferCallback successCallback,
+      AudioBufferCallback errorCallback]) native;
+
   @DomName('AudioContext.decodeAudioData')
   Future<AudioBuffer> decodeAudioData(ByteBuffer audioData) {
     var completer = new Completer<AudioBuffer>();
     _decodeAudioData(audioData,
         (value) { completer.complete(value); },
         (error) {
           if (error == null) {
             completer.completeError('');
           } else {
             completer.completeError(error);
           }
         });
     return completer.future;
   }
+$else
+  @DomName('AudioContext.decodeAudioData')
+  Future<AudioBuffer> decodeAudioData(ByteBuffer audioData,
+      [AudioBufferCallback successCallback,
+      AudioBufferCallback errorCallback]) {
+    if (errorCallback != null) {
+      return convertNativePromiseToDartFuture(_blink.BlinkAudioContext.instance.decodeAudioData_Callback_3_(
+          this, audioData, successCallback, errorCallback));
+    }
+    if (successCallback != null) {
+      return convertNativePromiseToDartFuture(_blink.BlinkAudioContext.instance
+          .decodeAudioData_Callback_2_(this, audioData, successCallback));
+    }
+    return convertNativePromiseToDartFuture(_blink.BlinkAudioContext.instance
+        .decodeAudioData_Callback_1_(this, audioData));
+  }
+$endif
 }