Implemented passing media track info from ffmpeg into blink

media/filters/ffmpeg_demuxer.h

Index: media/filters/ffmpeg_demuxer.h
diff --git a/media/filters/ffmpeg_demuxer.h b/media/filters/ffmpeg_demuxer.h
index 9bad5ff482d0e50218bf3ddc9a69ee3ea0fd9ced..dbaaea2babaeaeffddbbe1fbb261659faff8c9c9 100644
--- a/media/filters/ffmpeg_demuxer.h
+++ b/media/filters/ffmpeg_demuxer.h
@@ -190,6 +190,7 @@ class MEDIA_EXPORT FFmpegDemuxer : public Demuxer {
   FFmpegDemuxer(const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
                 DataSource* data_source,
                 const EncryptedMediaInitDataCB& encrypted_media_init_data_cb,
+                const MediaTracksUpdatedCB& media_tracks_updated_cb,
                 const scoped_refptr<MediaLog>& media_log);
   ~FFmpegDemuxer() override;
 
@@ -329,6 +330,8 @@ class MEDIA_EXPORT FFmpegDemuxer : public Demuxer {
 
   const EncryptedMediaInitDataCB encrypted_media_init_data_cb_;
 
+  const MediaTracksUpdatedCB media_tracks_updated_cb_;
+
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<FFmpegDemuxer> weak_factory_;