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

ui/gfx/size_f.h

 // Copyright (c) 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.
 
 #ifndef UI_GFX_SIZE_F_H_
 #define UI_GFX_SIZE_F_H_
 
 #include <string>
 
 #include "ui/base/ui_export.h"
 #include "ui/gfx/size_base.h"
 
 namespace gfx {
 
 // A floating version of gfx::Size.
 class UI_EXPORT SizeF : public SizeBase<SizeF, float> {
  public:
   SizeF();
   SizeF(float width, float height);
   ~SizeF();
 
-  SizeF Scale(float scale) const WARN_UNUSED_RESULT {
-    return Scale(scale, scale);
+  void Scale(float scale) {
+    Scale(scale, scale);
   }
 
-  SizeF Scale(float x_scale, float y_scale) const WARN_UNUSED_RESULT {
-    return SizeF(width() * x_scale, height() * y_scale);
+  void Scale(float x_scale, float y_scale) {
+    SetSize(width() * x_scale, height() * y_scale);
   }
 
   std::string ToString() const;
 };
 
 inline bool operator==(const SizeF& lhs, const SizeF& rhs) {
   return lhs.width() == rhs.width() && lhs.height() == rhs.height();
 }
 
 inline bool operator!=(const SizeF& lhs, const SizeF& rhs) {
   return !(lhs == rhs);
 }
 
+UI_EXPORT SizeF ScaleSize(const SizeF& p, float x_scale, float y_scale);
+
+inline SizeF ScaleSize(const SizeF& p, float scale) {
+  return ScaleSize(p, scale, scale);
+}
+
 #if !defined(COMPILER_MSVC)
 extern template class SizeBase<SizeF, float>;
 #endif
 
 }  // namespace gfx
 
 #endif  // UI_GFX_SIZE_F_H_