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

cc/quads/shared_quad_state.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_SHARED_QUAD_STATE_H_
 #define CC_QUADS_SHARED_QUAD_STATE_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "cc/base/cc_export.h"
 #include "third_party/skia/include/core/SkXfermode.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/transform.h"
 
 namespace base {
 class Value;
 }
 
 namespace cc {
 
 class CC_EXPORT SharedQuadState {
  public:
   static scoped_ptr<SharedQuadState> Create();
   ~SharedQuadState();
 
   scoped_ptr<SharedQuadState> Copy() const;
 
   void SetAll(const gfx::Transform& content_to_target_transform,
               gfx::Size content_bounds,
-              gfx::Rect visible_content_rect,
-              gfx::Rect clip_rect,
+              const gfx::Rect& visible_content_rect,
+              const gfx::Rect& clip_rect,
               bool is_clipped,
               float opacity,
               SkXfermode::Mode blend_mode);
   scoped_ptr<base::Value> AsValue() const;
 
   // Transforms from quad's original content space to its target content space.
   gfx::Transform content_to_target_transform;
   // This size lives in the content space for the quad's originating layer.
   gfx::Size content_bounds;
   // This rect lives in the content space for the quad's originating layer.
   gfx::Rect visible_content_rect;
   // This rect lives in the target content space.
   gfx::Rect clip_rect;
   bool is_clipped;
   float opacity;
   SkXfermode::Mode blend_mode;
 
  private:
   SharedQuadState();
 };
 
 }  // namespace cc
 
 #endif  // CC_QUADS_SHARED_QUAD_STATE_H_