Add support for unmixed audio from remote WebRTC remote tracks.

content/renderer/media/media_stream_track.h

Index: content/renderer/media/media_stream_track.h
diff --git a/content/renderer/media/media_stream_track.h b/content/renderer/media/media_stream_track.h
index 9ba3c68b0799680f65652561be02484f34b37ba7..74b2009652768ac1634525aabb1e6e9bf6a12579 100644
--- a/content/renderer/media/media_stream_track.h
+++ b/content/renderer/media/media_stream_track.h
@@ -8,6 +8,7 @@
 #include "base/compiler_specific.h"
 #include "base/threading/thread_checker.h"
 #include "content/common/content_export.h"
+#include "media/audio/audio_parameters.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamTrack.h"
 
 namespace webrtc {
@@ -16,6 +17,8 @@ class AudioTrackInterface;
 
 namespace content {
 
+class MediaStreamAudioSink;
+
 // MediaStreamTrack is a Chrome representation of blink::WebMediaStreamTrack.
 // It is owned by blink::WebMediaStreamTrack as
 // blink::WebMediaStreamTrack::ExtraData.
@@ -31,9 +34,6 @@ class CONTENT_EXPORT MediaStreamTrack
 
   virtual void Stop() = 0;
 
-  // TODO(tommi, xians): Remove this method.
-  virtual webrtc::AudioTrackInterface* GetAudioAdapter();
-
   bool is_local_track() const { return is_local_track_; }
 
  protected:
@@ -42,9 +42,39 @@ class CONTENT_EXPORT MediaStreamTrack
   // Used to DCHECK that we are called on Render main Thread.
   base::ThreadChecker main_render_thread_checker_;
 
+ private:
   DISALLOW_COPY_AND_ASSIGN(MediaStreamTrack);
 };
 
+class CONTENT_EXPORT MediaStreamAudioTrack : public MediaStreamTrack {

[perkj_chrome, 2015/12/11 12:31:38]

please move to separate file. See MediaStreamVideoTrack

[tommi (sloooow) - chröme, 2015/12/11 15:36:51]

Done.

+ public:
+  explicit MediaStreamAudioTrack(bool is_local_track);
+  ~MediaStreamAudioTrack() override;
+
+  static MediaStreamAudioTrack* GetTrack(
+      const blink::WebMediaStreamTrack& track);
+
+  // 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.
+  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.
+  virtual media::AudioParameters GetOutputFormat() const = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(MediaStreamAudioTrack);
+};
+
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_MEDIA_STREAM_TRACK_H_