[cc] Forward BeginFrameAcks through DirectCFS and CFSSupport.

cc/test/fake_compositor_frame_sink_client.h

Index: cc/test/fake_compositor_frame_sink_client.h
diff --git a/cc/test/fake_compositor_frame_sink_client.h b/cc/test/fake_compositor_frame_sink_client.h
index 91536e70557af23e4319fc0ed9f2e60cc8fd069b..a0049126158262976aafc30d2da89588a43d6bcb 100644
--- a/cc/test/fake_compositor_frame_sink_client.h
+++ b/cc/test/fake_compositor_frame_sink_client.h
@@ -14,7 +14,7 @@ class FakeCompositorFrameSinkClient : public CompositorFrameSinkClient {
  public:
   FakeCompositorFrameSinkClient() : memory_policy_(0) {}
 
-  void SetBeginFrameSource(BeginFrameSource* source) override {}
+  void SetBeginFrameSource(BeginFrameSource* source) override;
   void DidReceiveCompositorFrameAck() override;
   void ReclaimResources(const ReturnedResourceArray& resources) override {}
   void DidLoseCompositorFrameSink() override;
@@ -35,10 +35,13 @@ class FakeCompositorFrameSinkClient : public CompositorFrameSinkClient {
 
   const ManagedMemoryPolicy& memory_policy() const { return memory_policy_; }
 
+  BeginFrameSource* begin_frame_source() const { return begin_frame_source_; }
+
  private:
   int ack_count_ = 0;
   bool did_lose_compositor_frame_sink_called_ = false;
   ManagedMemoryPolicy memory_policy_;
+  BeginFrameSource* begin_frame_source_;
 };
 
 }  // namespace cc