Add fixed raster scale use counter histograms.

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 993780c0dce7f902c5e43b1678bd2bc881fef938..5bad9b0a7c2518fe7c9a1a23a74efc2d1ead33c6 100644
--- a/cc/layers/layer_impl.h
+++ b/cc/layers/layer_impl.h
@@ -513,6 +513,11 @@ class CC_EXPORT LayerImpl {
 
   void ClearLinksToOtherLayers();
 
+  void SetHasWillChangeTransformHint(bool has_will_change);
+  bool has_will_change_transform_hint() const {
+    return has_will_change_transform_hint_;
+  }
+
  protected:
   LayerImpl(LayerTreeImpl* layer_impl,
             int id,
@@ -645,6 +650,7 @@ class CC_EXPORT LayerImpl {
   std::unique_ptr<RenderSurfaceImpl> render_surface_;
 
   bool scrolls_drawn_descendant_;
+  bool has_will_change_transform_hint_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerImpl);
 };