Allow callers of TimeSource::GetWallClockTime() to suspend time.

media/renderers/audio_renderer_impl.cc

 // 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.
 
 #include "media/renderers/audio_renderer_impl.h"
 
 #include <math.h>
 
 #include <algorithm>
 
@@ skipping 148 matching lines @@
   base::TimeDelta current_media_time;
   {
     base::AutoLock auto_lock(lock_);
     current_media_time = audio_clock_->front_timestamp();
   }
 
   DVLOG(2) << __FUNCTION__ << ": " << current_media_time;
   return current_media_time;
 }
 
-base::TimeTicks AudioRendererImpl::GetWallClockTime(base::TimeDelta time) {
-  base::AutoLock auto_lock(lock_);
-  if (last_render_ticks_.is_null() || playback_rate_ == 0.0)
+base::TimeTicks AudioRendererImpl::GetWallClockTime(base::TimeDelta time,
+                                                    int request_flags) {
+  if (request_flags & SUSPEND_TIME)
+    lock_.Acquire();
+
+  lock_.AssertAcquired();
+  if (last_render_ticks_.is_null() || playback_rate_ == 0.0) {
+    lock_.Release();
     return base::TimeTicks();
+  }
 
   base::TimeDelta base_time;
   if (time < audio_clock_->front_timestamp()) {
     // See notes about |time| values less than |base_time| in TimeSource header.
     base_time = audio_clock_->front_timestamp();
   } else if (time > audio_clock_->back_timestamp()) {
     base_time = audio_clock_->back_timestamp();
   } else {
     // No need to estimate time, so return the actual wallclock time.
-    return last_render_ticks_ + audio_clock_->TimeUntilPlayback(time);
+    const base::TimeTicks result =
+        last_render_ticks_ + audio_clock_->TimeUntilPlayback(time);
+
+    if (request_flags & RESUME_TIME)
+      lock_.Release();
+
+    return result;
   }
 
   // In practice, most calls will be estimates given the relatively small window
   // in which clients can get the actual time.
-  return last_render_ticks_ + audio_clock_->TimeUntilPlayback(base_time) +
-         base::TimeDelta::FromMicroseconds((time - base_time).InMicroseconds() /
-                                           playback_rate_);
+  const base::TimeTicks result =
+      last_render_ticks_ + audio_clock_->TimeUntilPlayback(base_time) +
+      base::TimeDelta::FromMicroseconds((time - base_time).InMicroseconds() /
+                                        playback_rate_);
+
+  if (request_flags & RESUME_TIME)
+    lock_.Release();
+
+  return result;
 }
 
 TimeSource* AudioRendererImpl::GetTimeSource() {
   return this;
 }
 
 void AudioRendererImpl::Flush(const base::Closure& callback) {
   DVLOG(1) << __FUNCTION__;
   DCHECK(task_runner_->BelongsToCurrentThread());
 
@@ skipping 550 matching lines @@
            << buffering_state;
   DCHECK_NE(buffering_state_, buffering_state);
   lock_.AssertAcquired();
   buffering_state_ = buffering_state;
 
   task_runner_->PostTask(FROM_HERE,
                          base::Bind(buffering_state_cb_, buffering_state_));
 }
 
 }  // namespace media