Implement disabling and enabling media tracks

media/filters/chunk_demuxer.h

Index: media/filters/chunk_demuxer.h
diff --git a/media/filters/chunk_demuxer.h b/media/filters/chunk_demuxer.h
index 8893b01b07a3dff19e917f13d2b0186dd4850a23..9c580d2bf2c5252894666ea0cd4f83a0c67761ef 100644
--- a/media/filters/chunk_demuxer.h
+++ b/media/filters/chunk_demuxer.h
@@ -107,6 +107,9 @@ class MEDIA_EXPORT ChunkDemuxerStream : public DemuxerStream {
   VideoDecoderConfig video_decoder_config() override;
   bool SupportsConfigChanges() override;
   VideoRotation video_rotation() override;
+  bool enabled() const override;
+  void set_enabled(bool enabled, base::TimeDelta timestamp) override;
+  void SetStreamRestartedCB(const StreamRestartedCB& cb) override;
 
   // Returns the text track configuration.  It is an error to call this method
   // if type() != TEXT.
@@ -150,6 +153,8 @@ class MEDIA_EXPORT ChunkDemuxerStream : public DemuxerStream {
   ReadCB read_cb_;
   bool splice_frames_enabled_;
   bool partial_append_window_trimming_enabled_;
+  bool is_enabled_;
+  StreamRestartedCB stream_restarted_cb_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(ChunkDemuxerStream);
 };
@@ -222,6 +227,12 @@ class MEDIA_EXPORT ChunkDemuxer : public Demuxer {
   // Gets the currently buffered ranges for the specified ID.
   Ranges<base::TimeDelta> GetBufferedRanges(const std::string& id) const;
 
+  void OnEnabledAudioTracksChanged(const std::vector<MediaTrack::Id>& track_ids,
+                                   base::TimeDelta currTime) override;
+  // |track_ids| is either empty or contains a single video track id.
+  void OnSelectedVideoTrackChanged(const std::vector<MediaTrack::Id>& track_ids,
+                                   base::TimeDelta currTime) override;
+
   // Appends media data to the source buffer associated with |id|, applying
   // and possibly updating |*timestamp_offset| during coded frame processing.
   // |append_window_start| and |append_window_end| correspond to the MSE spec's