Plumb render view ID from audio-related code in renderer through IPCs to AudioRendererHost in brows…

content/renderer/media/audio_message_filter.h

Index: content/renderer/media/audio_message_filter.h
diff --git a/content/renderer/media/audio_message_filter.h b/content/renderer/media/audio_message_filter.h
index ce57ad940149fd49a319f3e08146072429f0324f..a2ccd097ff3aba38ce968658ba4345827f5a851d 100644
--- a/content/renderer/media/audio_message_filter.h
+++ b/content/renderer/media/audio_message_filter.h
@@ -20,24 +20,14 @@
 #include "media/audio/audio_output_ipc.h"
 
 class CONTENT_EXPORT AudioMessageFilter
-    : public IPC::ChannelProxy::MessageFilter,
-      public NON_EXPORTED_BASE(media::AudioOutputIPC) {
+    : public IPC::ChannelProxy::MessageFilter {
  public:
   AudioMessageFilter();
 
-  // Getter for the one AudioMessageFilter object.
-  static AudioMessageFilter* Get();
-
-  // media::AudioOutputIPCDelegate implementation.
-  virtual int AddDelegate(media::AudioOutputIPCDelegate* delegate) OVERRIDE;
-  virtual void RemoveDelegate(int id) OVERRIDE;
-  virtual void CreateStream(int stream_id,
-      const media::AudioParameters& params, int input_channels) OVERRIDE;
-  virtual void PlayStream(int stream_id) OVERRIDE;
-  virtual void PauseStream(int stream_id) OVERRIDE;
-  virtual void FlushStream(int stream_id) OVERRIDE;
-  virtual void CloseStream(int stream_id) OVERRIDE;
-  virtual void SetVolume(int stream_id, double volume) OVERRIDE;
+  // Creates an AudioOutputIPC which is used to send messages to/from the host
+  // on behalf of a render view (i.e., the view which contains the object
+  // rendering the audio).
+  scoped_ptr<media::AudioOutputIPC> CreateAudioOutputIPC(int render_view_id);
 
   // IPC::ChannelProxy::MessageFilter override. Called on IO thread.
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
@@ -52,6 +42,8 @@ class CONTENT_EXPORT AudioMessageFilter
   FRIEND_TEST_ALL_PREFIXES(AudioMessageFilterTest, Basic);
   FRIEND_TEST_ALL_PREFIXES(AudioMessageFilterTest, Delegates);
 
+  class AudioOutputIPCImpl;
+
   // Sends an IPC message using |channel_|.
   bool Send(IPC::Message* message);
 
@@ -69,9 +61,6 @@ class CONTENT_EXPORT AudioMessageFilter
   void OnStreamStateChanged(int stream_id,
                             media::AudioOutputIPCDelegate::State state);
 
-  // The singleton instance for this filter.
-  static AudioMessageFilter* filter_;
-
   // A map of stream ids to delegates.
   IDMap<media::AudioOutputIPCDelegate> delegates_;