[#2] Pass gfx structs by const ref (gfx::Rect, gfx::RectF)

cc/quads/checkerboard_draw_quad.h

 // 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.
 
 #ifndef CC_QUADS_CHECKERBOARD_DRAW_QUAD_H_
 #define CC_QUADS_CHECKERBOARD_DRAW_QUAD_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "cc/base/cc_export.h"
 #include "cc/quads/draw_quad.h"
 #include "third_party/skia/include/core/SkColor.h"
 
 namespace cc {
 
 class CC_EXPORT CheckerboardDrawQuad : public DrawQuad {
  public:
   static scoped_ptr<CheckerboardDrawQuad> Create();
 
   void SetNew(const SharedQuadState* shared_quad_state,
-              gfx::Rect rect,
+              const gfx::Rect& rect,
               SkColor color);
 
   void SetAll(const SharedQuadState* shared_quad_state,
-              gfx::Rect rect,
-              gfx::Rect opaque_rect,
-              gfx::Rect visible_rect,
+              const gfx::Rect& rect,
+              const gfx::Rect& opaque_rect,
+              const gfx::Rect& visible_rect,
               bool needs_blending,
               SkColor color);
 
   SkColor color;
 
   virtual void IterateResources(const ResourceIteratorCallback& callback)
     OVERRIDE;
 
   static const CheckerboardDrawQuad* MaterialCast(const DrawQuad*);
 
  private:
   virtual void ExtendValue(base::DictionaryValue* value) const OVERRIDE;
   CheckerboardDrawQuad();
 };
 
 }  // namespace cc
 
 #endif  // CC_QUADS_CHECKERBOARD_DRAW_QUAD_H_