cc: Video layers without a frame should not occlude

media/blink/video_frame_compositor.cc

Index: media/blink/video_frame_compositor.cc
diff --git a/media/blink/video_frame_compositor.cc b/media/blink/video_frame_compositor.cc
index 3e19254f67bc5ed4229dd09798b8028516393466..648e585466ca8ce6b6b293387808d82187ddb7f0 100644
--- a/media/blink/video_frame_compositor.cc
+++ b/media/blink/video_frame_compositor.cc
@@ -124,6 +124,11 @@ bool VideoFrameCompositor::UpdateCurrentFrame(base::TimeTicks deadline_min,
   return CallRender(deadline_min, deadline_max, false);
 }
 
+bool VideoFrameCompositor::HasCurrentFrame() {
+  DCHECK(compositor_task_runner_->BelongsToCurrentThread());
+  return current_frame_;
+}
+
 void VideoFrameCompositor::Start(RenderCallback* callback) {
   TRACE_EVENT0("media", "VideoFrameCompositor::Start");