Implement disabling and enabling media tracks

media/base/demuxer.h

Index: media/base/demuxer.h
diff --git a/media/base/demuxer.h b/media/base/demuxer.h
index 9c6607f9cb212555c5eee02d494b2b2e407d52a5..429b565ba0bb929225335f09b458b6a241ad4774 100644
--- a/media/base/demuxer.h
+++ b/media/base/demuxer.h
@@ -17,6 +17,7 @@
 #include "media/base/demuxer_stream_provider.h"
 #include "media/base/eme_constants.h"
 #include "media/base/media_export.h"
+#include "media/base/media_track.h"
 #include "media/base/pipeline_status.h"
 #include "media/base/ranges.h"
 
@@ -135,6 +136,14 @@ class MEDIA_EXPORT Demuxer : public DemuxerStreamProvider {
   // Returns the memory usage in bytes for the demuxer.
   virtual int64_t GetMemoryUsage() const = 0;
 
+  virtual void OnEnabledAudioTracksChanged(
+      const std::vector<MediaTrack::Id>& track_ids,
+      base::TimeDelta currTime) = 0;
+  // |track_ids| is either empty or contains a single video track id.

[chcunningham, 2016/06/24 23:32:55]

New line above this comment?

[servolk, 2016/06/25 00:36:33]

Done.

+  virtual void OnSelectedVideoTrackChanged(
+      const std::vector<MediaTrack::Id>& track_ids,
+      base::TimeDelta currTime) = 0;
+
  private:
   DISALLOW_COPY_AND_ASSIGN(Demuxer);
 };