Add fixed raster scale use counter histograms.

cc/blink/web_layer_impl.h

Index: cc/blink/web_layer_impl.h
diff --git a/cc/blink/web_layer_impl.h b/cc/blink/web_layer_impl.h
index 6df940a3da60ac62f17b46fb81079ef1b4e9be7b..21d1038c90e1baf5f9e97be1ed0ad0bdeb31a5da 100644
--- a/cc/blink/web_layer_impl.h
+++ b/cc/blink/web_layer_impl.h
@@ -134,6 +134,8 @@ class WebLayerImpl : public blink::WebLayer {
   void setScrollParent(blink::WebLayer* parent) override;
   void setClipParent(blink::WebLayer* parent) override;
 
+  void setHasWillChangeTransformHint(bool has_will_change) override;

[danakj, 2016/05/05 00:09:49]

group this with the rest, no need for whitespace. these should all be part of
the WebLayer implementation block.

[vmpstr, 2016/05/05 01:33:50]

Done.

+
  protected:
   scoped_refptr<cc::Layer> layer_;