Enable audio/video tag in content_shell

content/browser/renderer_host/media/audio_renderer_host.h

Index: content/browser/renderer_host/media/audio_renderer_host.h
diff --git a/content/browser/renderer_host/media/audio_renderer_host.h b/content/browser/renderer_host/media/audio_renderer_host.h
index d24dfdbe1487bc932b10491ed2c389f1befa8dfd..75696897aa7e66bb49c7c1b0320668d350bfaa00 100644
--- a/content/browser/renderer_host/media/audio_renderer_host.h
+++ b/content/browser/renderer_host/media/audio_renderer_host.h
@@ -178,10 +178,18 @@ class CONTENT_EXPORT AudioRendererHost
   // event is received.
   AudioEntry* LookupByController(media::AudioOutputController* controller);
 
-  // Return resource_context_->media_observer() or a cached copy thereof.
-  // This is necessary because resource_context_ can be destructed before all
+  // Notifies media_observer() about various audio stream events.
+  void OnSetAudioStreamPlaying(int stream_id, bool playing);
+  void OnSetAudioStreamStatus(int stream_id, const std::string& status);
+  void OnSetAudioStreamVolume(int stream_id, double volume);
+  void OnDeleteAudioStream(int stream_id);
+
+  // Return the MediaObserver from |resource_context_| or a cached copy thereof.
+  // This is necessary because |resource_context_| can be destructed before all
   // AudioEntries have been deleted. The MediaObserver's lifetime is tied to
   // that of the IO thread, so this is safe.
+  // TODO(vrk): Saving the |media_observer_| pointer is a hack! We shouldn't
+  // need to do this and the field should be removed. See crbug.com/116906.
   content::MediaObserver* GetMediaObserver();
 
   // A map of stream IDs to audio sources.