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 ee2634b70746e9adc38f1625d5a14acc702d7290..e17953bbec37bfd478e2cc1e9ff9f4c7c579ea6f 100644
--- a/cc/layers/layer_impl.h
+++ b/cc/layers/layer_impl.h
@@ -526,6 +526,11 @@ 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,
@@ -660,6 +665,7 @@ class CC_EXPORT LayerImpl {
   bool scrolls_drawn_descendant_;
   // If true, the layer or one of its descendants has a touch handler.
   bool layer_or_descendant_has_touch_handler_;
+  bool has_will_change_transform_hint_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerImpl);
 };