cc: Various code safety improvements in video compositing code.

cc/test/fake_video_frame_provider.cc

Index: cc/test/fake_video_frame_provider.cc
diff --git a/cc/test/fake_video_frame_provider.cc b/cc/test/fake_video_frame_provider.cc
index f008d9fda4c35718933288e5a4f20f4e993df8f4..9e6fd15f87cb320c50e01a53b77c222a0dfc10b1 100644
--- a/cc/test/fake_video_frame_provider.cc
+++ b/cc/test/fake_video_frame_provider.cc
@@ -22,4 +22,8 @@ scoped_refptr<media::VideoFrame> FakeVideoFrameProvider::GetCurrentFrame() {
   return frame_;
 }
 
+void FakeVideoFrameProvider::SendDidReceiveFrame() {
+  client_->DidReceiveFrame();
+}
+
 }  // namespace cc