Allow muting/unmuting audio through media track API

media/base/demuxer.h

Index: media/base/demuxer.h
diff --git a/media/base/demuxer.h b/media/base/demuxer.h
index 027264ba79fb916f0359a983d4f4dc4519ccba80..6ffe5d264b237969e5d186413f0e0e9efebcb4d9 100644
--- a/media/base/demuxer.h
+++ b/media/base/demuxer.h
@@ -67,7 +67,7 @@ class MEDIA_EXPORT Demuxer : public DemuxerStreamProvider {
       EncryptedMediaInitDataCB;
 
   // Notifies demuxer clients that media track configuration has been updated
-  // (e.g. the inital stream metadata has been parsed successfully, or a new
+  // (e.g. the initial stream metadata has been parsed successfully, or a new
   // init segment has been parsed successfully in MSE case).
   typedef base::Callback<void(scoped_ptr<MediaTracks>)> MediaTracksUpdatedCB;
 
@@ -134,6 +134,15 @@ class MEDIA_EXPORT Demuxer : public DemuxerStreamProvider {
   // Returns the memory usage in bytes for the demuxer.
   virtual int64_t GetMemoryUsage() const = 0;
 
+  // Notifies the demuxer that track ids has been assigned to a media tracks.

[wolenetz, 2016/04/08 23:32:31]

nit: blink track ids, right?
nits: Also, s/has/have/ and s/a media tracks/|tracks|/.

[servolk, 2016/04/08 23:47:20]

Done.

+  virtual void OnTrackIdsAssigned(const MediaTracks& tracks,
+                                  const std::vector<unsigned>& track_ids) = 0;

[wolenetz, 2016/04/08 23:32:31]

Comment is needed to describe that |tracks|.tracks() size must be the same as
|track_ids|, and that their sequences match, such that the association of each
track id to a MediaTrack is well-defined here.

[servolk, 2016/04/08 23:47:20]

Done.

+
+  // Finds a DemuxerStream corresponding to the given blink |track_id|. Note
+  // that the input track id is blink track id and not bytestream track id.
+  virtual const DemuxerStream* GetDemuxerStreamByTrackId(
+      unsigned track_id) const = 0;
+
  private:
   DISALLOW_COPY_AND_ASSIGN(Demuxer);
 };