Add WebMediaPlayer::timelineOffset() support to WebMediaPlayerImpl.

media/base/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.
 
 #ifndef MEDIA_BASE_DEMUXER_H_
 #define MEDIA_BASE_DEMUXER_H_
 
 #include <vector>
 
 #include "base/time/time.h"
@@ skipping 69 matching lines @@
   // TODO(scherkus): this might not be needed http://crbug.com/234708
   virtual void OnAudioRendererDisabled() = 0;
 
   // Returns the first stream of the given stream type (which is not allowed
   // to be DemuxerStream::TEXT), or NULL if that type of stream is not present.
   virtual DemuxerStream* GetStream(DemuxerStream::Type type) = 0;
 
   // Returns the starting time for the media file.
   virtual base::TimeDelta GetStartTime() const = 0;
 
+  // Returns Time represented by presentation timestamp 0.
+  // If the timstamps are not associated with a Time, then
+  // a null Time is returned.
+  virtual base::Time GetTimelineOffset() const = 0;
+
  private:
   DISALLOW_COPY_AND_ASSIGN(Demuxer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_DEMUXER_H_