MediaStream audio sourcing: Bypass audio processing for non-WebRTC cases.

content/renderer/media/media_stream_audio_track.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_TRACK_H_
 #define CONTENT_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_TRACK_H_
 
 #include "base/macros.h"
 #include "content/renderer/media/media_stream_track.h"
 
@@ skipping 15 matching lines @@
 
   // Add a sink to the track. This function will trigger a OnSetFormat()
   // call on the |sink|.
   // Called on the main render thread.
   virtual void AddSink(MediaStreamAudioSink* sink) = 0;
 
   // Remove a sink from the track.
   // Called on the main render thread.
   virtual void RemoveSink(MediaStreamAudioSink* sink) = 0;
 
-  // TODO(tommi, xians): Remove this method.
+  // NOTE: This can return null if the WebRTC audio pipeline is not being used.
+  // TODO(tommi, xians): Remove this method.  http://crbug.com/577874
   virtual webrtc::AudioTrackInterface* GetAudioAdapter();
 
   // Returns the output format of the capture source. May return an invalid
   // AudioParameters if the format is not yet available.
   // Called on the main render thread.
   // TODO(tommi): This method appears to only be used by Pepper and in fact
   // does not appear to be necessary there.  We should remove it since it adds
   // to the complexity of all types of audio tracks+source implementations.
+  // http://crbug.com/577874
   virtual media::AudioParameters GetOutputFormat() const = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MediaStreamAudioTrack);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_TRACK_H_