ui: Make gfx::Size::Scale() mutate the class. Add gfx::ScaleSize() similar to Rect/Point.

cc/contents_scaling_layer.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 
 #include "cc/contents_scaling_layer.h"
 #include "ui/gfx/size_conversions.h"
 
 namespace cc {
 
 ContentsScalingLayer::ContentsScalingLayer()
     : m_contentsScale(1.0) {
 }
 
 ContentsScalingLayer::~ContentsScalingLayer() {
 }
 
 gfx::Size ContentsScalingLayer::contentBounds() const {
-  return gfx::ToCeiledSize(bounds().Scale(contentsScaleX(), contentsScaleY()));
+  return gfx::ToCeiledSize(gfx::ScaleSize(bounds(), contentsScaleX(), contentsScaleY()));
 }
 
 float ContentsScalingLayer::contentsScaleX() const {
   return m_contentsScale;
 }
 
 float ContentsScalingLayer::contentsScaleY() const {
   return m_contentsScale;
 }
 
 void ContentsScalingLayer::setContentsScale(float contentsScale) {
   if (m_contentsScale == contentsScale)
     return;
   m_contentsScale = contentsScale;
   setNeedsDisplay();
 }
 
 }  // namespace cc