Allow muting/unmuting audio through media track API

third_party/WebKit/Source/web/WebRuntimeFeatures.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 302 matching lines @@
 void WebRuntimeFeatures::enableRenderingPipelineThrottling(bool enable)
 {
     RuntimeEnabledFeatures::setRenderingPipelineThrottlingEnabled(enable);
 }
 
 bool WebRuntimeFeatures::isServiceWorkerExtendableMessageEventEnabled()
 {
     return RuntimeEnabledFeatures::serviceWorkerExtendableMessageEventEnabled();
 }
 
+bool WebRuntimeFeatures::audioVideoTracksEnabled()
+{
+    return RuntimeEnabledFeatures::audioVideoTracksEnabled();
+}
+
 } // namespace blink