Freeze the reported media time while audio is restarted

media/renderers/renderer_impl.cc

Index: media/renderers/renderer_impl.cc
diff --git a/media/renderers/renderer_impl.cc b/media/renderers/renderer_impl.cc
index eb5710d2eea5f40c4f634d063a62e29f9547c162..61cfb40e8a79f3517facc33b221f393d91948233 100644
--- a/media/renderers/renderer_impl.cc
+++ b/media/renderers/renderer_impl.cc
@@ -264,6 +264,11 @@ void RendererImpl::SetVolume(float volume) {
 base::TimeDelta RendererImpl::GetMediaTime() {
   // No BelongsToCurrentThread() checking because this can be called from other
   // threads.
+  base::AutoLock lock(restarting_audio_lock_);
+  if (restarting_audio_) {
+    DCHECK_NE(kNoTimestamp, restarting_audio_time_);
+    return restarting_audio_time_;
+  }

[xhwang, 2017/05/24 00:23:41]

If time_source_->CurrentMediaTime() calls back into this class we could end up
in a deadlock. I don't think this will happen, but it's better to err on the
safe side.

To fix that, can we put l.267-271 in a {} block?

[servolk, 2017/05/24 00:28:00]

Done.

   return time_source_->CurrentMediaTime();
 }
 
@@ -575,7 +580,11 @@ void RendererImpl::OnStreamStatusChanged(DemuxerStream* stream,
   } else if (stream->type() == DemuxerStream::AUDIO) {
     DCHECK(audio_renderer_);
     DCHECK(time_source_);
-    restarting_audio_ = true;
+    {
+      base::AutoLock lock(restarting_audio_lock_);
+      restarting_audio_time_ = time;
+      restarting_audio_ = true;
+    }
     base::Closure handle_track_status_cb =
         base::Bind(stream == current_audio_stream_
                        ? &RendererImpl::RestartAudioRenderer
@@ -769,7 +778,11 @@ void RendererImpl::OnStreamRestartCompleted() {
            << " restarting_video_=" << restarting_video_;
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK(restarting_audio_ || restarting_video_);
-  restarting_audio_ = false;
+  {
+    base::AutoLock lock(restarting_audio_lock_);
+    restarting_audio_ = false;
+    restarting_audio_time_ = kNoTimestamp;
+  }
   restarting_video_ = false;
   if (!pending_actions_.empty()) {
     base::Closure closure = pending_actions_.front();