cc: Plumbing for impl thread micro benchmarks

cc/layers/layer_impl.h

Index: cc/layers/layer_impl.h
diff --git a/cc/layers/layer_impl.h b/cc/layers/layer_impl.h
index 9d3951b78afe49aeb46c6a24d90f877bad5a446c..e774dface1fecca13f058f0147218a283292066a 100644
--- a/cc/layers/layer_impl.h
+++ b/cc/layers/layer_impl.h
@@ -42,6 +42,7 @@ namespace cc {
 
 class LayerTreeHostImpl;
 class LayerTreeImpl;
+class MicroBenchmarkImpl;
 class QuadSink;
 class Renderer;
 class ScrollbarAnimationController;
@@ -490,6 +491,8 @@ class CC_EXPORT LayerImpl : LayerAnimationValueObserver {
   bool needs_push_properties() const { return true; }
   bool descendant_needs_push_properties() const { return true; }
 
+  virtual void RunMicroBenchmark(MicroBenchmarkImpl* benchmark);
+
  protected:
   LayerImpl(LayerTreeImpl* layer_impl, int id);