Implement disabling and enabling media tracks

media/base/demuxer_stream.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.
 
 #ifndef MEDIA_BASE_DEMUXER_STREAM_H_
 #define MEDIA_BASE_DEMUXER_STREAM_H_
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
+#include "base/time/time.h"
 #include "media/base/media_export.h"
 #include "media/base/video_rotation.h"
 
 namespace media {
 
 class AudioDecoderConfig;
 class DecoderBuffer;
 class VideoDecoderConfig;
 
 class MEDIA_EXPORT DemuxerStream {
@@ skipping 64 matching lines @@
   // A DemuxerStream that returns 'true' to this may return the 'kConfigChange'
   // status from a Read() call. In this case the client is expected to be
   // capable of taking appropriate action to handle config changes. Otherwise
   // audio_decoder_config() and video_decoder_config()'s return values are
   // guaranteed to remain constant, and the client may make optimizations based
   // on this.
   virtual bool SupportsConfigChanges() = 0;
 
   virtual VideoRotation video_rotation() = 0;
 
+  // Indicates whether a DemuxerStream is currently enabled (i.e. should be
+  // decoded and rendered) or not.
+  virtual bool enabled() const = 0;

[xhwang, 2016/06/04 00:09:43]

nit: add empty line

[servolk, 2016/06/09 21:00:13]

Done.

+  // Disables and re-enables the stream. Reading from a disabled stream will
+  // return an end-of-stream (EOS) buffer. When a stream is re-enabled, it needs
+  // to know the current playback position |timestamp| in order to resume
+  // reading data from a key frame preceeding the |timestamp|.
+  virtual void set_enabled(bool enabled, base::TimeDelta timestamp) = 0;
+
  protected:
   // Only allow concrete implementations to get deleted.
   virtual ~DemuxerStream();
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_DEMUXER_STREAM_H_