Change the TimeSource interface to return wallclock time for video.

media/filters/audio_clock.h

 // Copyright 2014 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_FILTERS_AUDIO_CLOCK_H_
 #define MEDIA_FILTERS_AUDIO_CLOCK_H_
 
 #include <deque>
 
 #include "base/time/time.h"
@@ skipping 59 matching lines @@
   // |      =   0 ms (media) |      = 500 ms (media) |      = 250 ms (media) |
   // +-----------------------+-----------------------+-----------------------+
   // ^                                                                       ^
   // front_timestamp() is equal to               back_timestamp() is equal to
   // |start_timestamp| since no                  amount of media frames tracked
   // media data has been played yet.             by AudioClock, which would be
   //                                             1000 + 500 + 250 = 1750 ms.
   base::TimeDelta front_timestamp() const { return front_timestamp_; }
   base::TimeDelta back_timestamp() const { return back_timestamp_; }
 
-  // Clients can provide |time_since_writing| to simulate the passage of time
-  // since last writing audio to get a more accurate current media timestamp.
-  //
-  // The value will be bounded between front_timestamp() and back_timestamp().
-  base::TimeDelta TimestampSinceWriting(
-      base::TimeDelta time_since_writing) const;
-
   // Returns the amount of wall time until |timestamp| will be played by the
   // audio hardware.
   //
   // |timestamp| must be within front_timestamp() and back_timestamp().
   base::TimeDelta TimeUntilPlayback(base::TimeDelta timestamp) const;
 
   // Returns the amount of contiguous media time buffered at the head of the
   // audio hardware buffer. Silence introduced into the audio hardware buffer is
   // treated as a break in media time.
   base::TimeDelta contiguous_audio_data_buffered() const {
@@ skipping 36 matching lines @@
   // Cached results of last call to WroteAudio().
   base::TimeDelta contiguous_audio_data_buffered_;
   base::TimeDelta contiguous_audio_data_buffered_at_same_rate_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioClock);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_AUDIO_CLOCK_H_