Deliver change notifications to SourceBuffer track lists.

third_party/WebKit/Source/modules/mediasource/SourceBuffer.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 158 matching lines @@
     std::unique_ptr<WebSourceBuffer> m_webSourceBuffer;
     Member<MediaSource> m_source;
     Member<TrackDefaultList> m_trackDefaults;
     Member<GenericEventQueue> m_asyncEventQueue;
 
     AtomicString m_mode;
     bool m_updating;
     double m_timestampOffset;
     Member<AudioTrackList> m_audioTracks;
     Member<VideoTrackList> m_videoTracks;
-    bool m_activeTrack = false;
     double m_appendWindowStart;
     double m_appendWindowEnd;
     bool m_firstInitializationSegmentReceived;
 
     Vector<unsigned char> m_pendingAppendData;
     size_t m_pendingAppendDataOffset;
     Member<AsyncMethodRunner<SourceBuffer>> m_appendBufferAsyncPartRunner;
 
     double m_pendingRemoveStart;
     double m_pendingRemoveEnd;
     Member<AsyncMethodRunner<SourceBuffer>> m_removeAsyncPartRunner;
 
     bool m_streamMaxSizeValid;
     unsigned long long m_streamMaxSize;
     Member<AsyncMethodRunner<SourceBuffer>> m_appendStreamAsyncPartRunner;
     Member<Stream> m_stream;
     std::unique_ptr<FileReaderLoader> m_loader;
 };
 
 } // namespace blink
 
 #endif // SourceBuffer_h