Implement disabling and enabling media tracks

media/filters/ffmpeg_demuxer.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Implements the Demuxer interface using FFmpeg's libavformat.  At this time
 // will support demuxing any audio/video format thrown at it.  The streams
 // output mime types audio/x-ffmpeg and video/x-ffmpeg and include an integer
 // key FFmpegCodecID which contains the CodecID enumeration value.  The CodecIDs
 // can be used to create and initialize the corresponding FFmpeg decoder.
 //
@@ skipping 93 matching lines @@
 
   // DemuxerStream implementation.
   Type type() const override;
   Liveness liveness() const override;
   void Read(const ReadCB& read_cb) override;
   void EnableBitstreamConverter() override;
   bool SupportsConfigChanges() override;
   AudioDecoderConfig audio_decoder_config() override;
   VideoDecoderConfig video_decoder_config() override;
   VideoRotation video_rotation() override;
+  bool enabled() const override;
+  void set_enabled(bool enabled, base::TimeDelta timestamp) override;
 
   void SetLiveness(Liveness liveness);
 
   // Returns the range of buffered data in this stream.
   Ranges<base::TimeDelta> GetBufferedRanges() const;
 
   // Returns elapsed time based on the already queued packets.
   // Used to determine stream duration when it's not known ahead of time.
   base::TimeDelta GetElapsedTime() const;
 
@@ skipping 41 matching lines @@
   std::unique_ptr<AudioDecoderConfig> audio_config_;
   std::unique_ptr<VideoDecoderConfig> video_config_;
   Type type_;
   Liveness liveness_;
   base::TimeDelta duration_;
   bool end_of_stream_;
   base::TimeDelta last_packet_timestamp_;
   base::TimeDelta last_packet_duration_;
   Ranges<base::TimeDelta> buffered_ranges_;
   VideoRotation video_rotation_;
+  bool is_enabled_;
 
   DecoderBufferQueue buffer_queue_;
   ReadCB read_cb_;
 
 #if defined(USE_PROPRIETARY_CODECS)
   std::unique_ptr<FFmpegBitstreamConverter> bitstream_converter_;
 #endif
 
   std::string encryption_key_id_;
   bool fixup_negative_timestamps_;
@@ skipping 163 matching lines @@
 
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<FFmpegDemuxer> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(FFmpegDemuxer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_FFMPEG_DEMUXER_H_