Revert of Remove AudioTrackRenderer

talk/media/base/audiorenderer.h

 /*
  * libjingle
  * Copyright 2013 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
@@ skipping 37 matching lines @@
     virtual void OnClose() = 0;
 
    protected:
     virtual ~Sink() {}
   };
 
   // Sets a sink to the AudioRenderer. There can be only one sink connected
   // to the renderer at a time.
   virtual void SetSink(Sink* sink) {}
 
+  // Add the WebRtc VoE channel to the renderer.
+  // For local stream, multiple WebRtc VoE channels can be connected to the
+  // renderer. While for remote stream, only one WebRtc VoE channel can be
+  // connected to the renderer.
+  // TODO(xians): Remove this interface after Chrome switches to the
+  // AudioRenderer::Sink interface.
+  virtual void AddChannel(int channel_id) {}
+
+  // Remove the WebRtc VoE channel from the renderer.
+  // This method is called when the VoE channel is going away.
+  // TODO(xians): Remove this interface after Chrome switches to the
+  // AudioRenderer::Sink interface.
+  virtual void RemoveChannel(int channel_id) {}
+
  protected:
   virtual ~AudioRenderer() {}
 };
 
 }  // namespace cricket
 
 #endif  // TALK_MEDIA_BASE_AUDIORENDERER_H_