Change the TimeSource interface to return wallclock time for video.

media/base/wall_clock_time_source.cc

 // 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.
 
 #include "media/base/wall_clock_time_source.h"
 
 #include "base/logging.h"
 #include "base/time/default_tick_clock.h"
+#include "media/base/buffers.h"

[xhwang, 2015/03/23 22:20:14]

not needed?

BTW, media/base/buffers.h should be renamed or cleaned...

[DaleCurtis, 2015/03/25 00:31:45]

Done.

 
 namespace media {
 
 WallClockTimeSource::WallClockTimeSource()
     : tick_clock_(new base::DefaultTickClock()),
       ticking_(false),
       playback_rate_(1.0f) {
 }
 
 WallClockTimeSource::~WallClockTimeSource() {
@@ skipping 34 matching lines @@
   base::AutoLock auto_lock(lock_);
   CHECK(!ticking_);
   base_time_ = time;
 }
 
 base::TimeDelta WallClockTimeSource::CurrentMediaTime() {
   base::AutoLock auto_lock(lock_);
   return CurrentMediaTime_Locked();
 }
 
-base::TimeDelta WallClockTimeSource::CurrentMediaTimeForSyncingVideo() {
-  return CurrentMediaTime();
+base::TimeTicks WallClockTimeSource::GetWallclockTimeForMediaTime(
+    base::TimeDelta time) {
+  base::AutoLock auto_lock(lock_);
+  if (!ticking_ || playback_rate_ == 0.0 || time < base_time_)

[xhwang, 2015/03/23 22:20:14]

Can we do DCHECK(time >= base_time_)?

[DaleCurtis, 2015/03/25 00:31:45]

Actually this condition was incorrect, it needs to support time < base_time_ if
playback rate changes yet the frame is still in the queue for some reason.

[xhwang, 2015/03/25 04:10:50]

Acknowledged.

+    return base::TimeTicks();
+
+  return reference_wall_ticks_ +
+         base::TimeDelta::FromMicroseconds(
+             (time - base_time_).InMicroseconds() * playback_rate_);
 }
 
 void WallClockTimeSource::SetTickClockForTesting(
     scoped_ptr<base::TickClock> tick_clock) {
   tick_clock_.swap(tick_clock);
 }
 
 base::TimeDelta WallClockTimeSource::CurrentMediaTime_Locked() {
   lock_.AssertAcquired();
   if (!ticking_)
     return base_time_;
 
   base::TimeTicks now = tick_clock_->NowTicks();
   return base_time_ +
          base::TimeDelta::FromMicroseconds(
              (now - reference_wall_ticks_).InMicroseconds() * playback_rate_);
 }
 
 }  // namespace media