[Media] Record time it takes to start rendering audio and video

media/base/pipeline_impl.cc

Index: media/base/pipeline_impl.cc
diff --git a/media/base/pipeline_impl.cc b/media/base/pipeline_impl.cc
index 85d470a022758459ac8f8f7f7bae599a088d7b76..1bf6e16d9a29fdbdef321e1035efe83cedff803d 100644
--- a/media/base/pipeline_impl.cc
+++ b/media/base/pipeline_impl.cc
@@ -114,6 +114,7 @@ class PipelineImpl::RendererWrapper : public DemuxerHost,
   void OnVideoNaturalSizeChange(const gfx::Size& size) final;
   void OnVideoOpacityChange(bool opaque) final;
   void OnDurationChange(base::TimeDelta duration) final;
+  void OnFirstFrameRender() final;
 
   // TextRenderer tasks and notifications.
   void OnTextRendererEnded();
@@ -679,6 +680,11 @@ void PipelineImpl::RendererWrapper::OnDurationChange(base::TimeDelta duration) {
   SetDuration(duration);
 }
 
+void PipelineImpl::RendererWrapper::OnFirstFrameRender() {
+  DCHECK(media_task_runner_->BelongsToCurrentThread());
+  NOTREACHED();
+}
+
 void PipelineImpl::RendererWrapper::OnTextRendererEnded() {
   DCHECK(media_task_runner_->BelongsToCurrentThread());
   media_log_->AddEvent(media_log_->CreateEvent(MediaLogEvent::TEXT_ENDED));