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

media/renderers/audio_renderer_impl.cc

Index: media/renderers/audio_renderer_impl.cc
diff --git a/media/renderers/audio_renderer_impl.cc b/media/renderers/audio_renderer_impl.cc
index dbc1b8ea8da918e670a03a2860606d5e1999808d..8dd7b0478edea416d03e815afb98bdf500b74aa0 100644
--- a/media/renderers/audio_renderer_impl.cc
+++ b/media/renderers/audio_renderer_impl.cc
@@ -166,10 +166,16 @@ base::TimeDelta AudioRendererImpl::CurrentMediaTime() {
   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()) {
@@ -179,14 +185,26 @@ base::TimeTicks AudioRendererImpl::GetWallClockTime(base::TimeDelta time) {
     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() {