Revert of Allow muting/unmuting audio through media track API

media/renderers/renderer_impl.h

Index: media/renderers/renderer_impl.h
diff --git a/media/renderers/renderer_impl.h b/media/renderers/renderer_impl.h
index 6345ecf1387838359c91692aeca0e571d2ee377f..fc17f6cbdf628ee1534e49890275856f156e6300 100644
--- a/media/renderers/renderer_impl.h
+++ b/media/renderers/renderer_impl.h
@@ -63,10 +63,6 @@ class MEDIA_EXPORT RendererImpl : public Renderer {
   base::TimeDelta GetMediaTime() final;
   bool HasAudio() final;
   bool HasVideo() final;
-  void OnEnabledAudioStreamsChanged(
-      const std::vector<const DemuxerStream*>& enabledAudioStreams) final;
-  void OnSelectedVideoStreamChanged(
-      const DemuxerStream* selectedVideoStream) final;
 
   // Helper functions for testing purposes. Must be called before Initialize().
   void DisableUnderflowForTesting();
@@ -155,9 +151,6 @@ class MEDIA_EXPORT RendererImpl : public Renderer {
   scoped_ptr<AudioRenderer> audio_renderer_;
   scoped_ptr<VideoRenderer> video_renderer_;
 
-  bool audio_stream_currently_disabled_ = false;
-  float audio_volume_ = 1.0f;
-
   // Renderer-provided time source used to control playback.
   TimeSource* time_source_;
   scoped_ptr<WallClockTimeSource> wall_clock_time_source_;