Revert of cc: Make PaintedScrollbarLayer not use ContentsScalingLayer

cc/layers/painted_scrollbar_layer_impl.h

Index: cc/layers/painted_scrollbar_layer_impl.h
diff --git a/cc/layers/painted_scrollbar_layer_impl.h b/cc/layers/painted_scrollbar_layer_impl.h
index 18df63de6dd368a951e3144c7b5e3ef687f324e4..8708b748662b0a7cdeefcbffa38310c8f4c3b97d 100644
--- a/cc/layers/painted_scrollbar_layer_impl.h
+++ b/cc/layers/painted_scrollbar_layer_impl.h
@@ -45,12 +45,6 @@
     thumb_ui_resource_id_ = uid;
   }
 
-  void set_internal_contents_scale_and_bounds(float content_scale,
-                                              const gfx::Size& content_bounds) {
-    internal_contents_scale_ = content_scale;
-    internal_content_bounds_ = content_bounds;
-  }
-
  protected:
   PaintedScrollbarLayerImpl(LayerTreeImpl* tree_impl,
                             int id,
@@ -69,9 +63,6 @@
   UIResourceId track_ui_resource_id_;
   UIResourceId thumb_ui_resource_id_;
 
-  float internal_contents_scale_;
-  gfx::Size internal_content_bounds_;
-
   int thumb_thickness_;
   int thumb_length_;
   int track_start_;