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

cc/layers/nine_patch_layer.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_LAYERS_NINE_PATCH_LAYER_H_
 #define CC_LAYERS_NINE_PATCH_LAYER_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "cc/base/cc_export.h"
 #include "cc/layers/layer.h"
@@ skipping 10 matching lines @@
  public:
   static scoped_refptr<NinePatchLayer> Create();
 
   virtual void PushPropertiesTo(LayerImpl* layer) OVERRIDE;
 
   // |border| is the space around the center rectangular region in layer space
   // (known as aperture in image space).  |border.x()| and |border.y()| are the
   // size of the left and top boundary, respectively.
   // |border.width()-border.x()| and |border.height()-border.y()| are the size
   // of the right and bottom boundary, respectively.
-  void SetBorder(gfx::Rect border);
+  void SetBorder(const gfx::Rect& border);
 
   // aperture is in the pixel space of the bitmap resource and refers to
   // the center patch of the ninepatch (which is unused in this
   // implementation). We split off eight rects surrounding it and stick them
   // on the edges of the layer. The corners are unscaled, the top and bottom
   // rects are x-stretched to fit, and the left and right rects are
   // y-stretched to fit.
-  void SetAperture(gfx::Rect aperture);
+  void SetAperture(const gfx::Rect& aperture);
   void SetFillCenter(bool fill_center);
 
  private:
   NinePatchLayer();
   virtual ~NinePatchLayer();
   virtual scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl)
       OVERRIDE;
 
   gfx::Rect border_;
   bool fill_center_;
 
   // The transparent center region that shows the parent layer's contents in
   // image space.
   gfx::Rect image_aperture_;
 
   DISALLOW_COPY_AND_ASSIGN(NinePatchLayer);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_NINE_PATCH_LAYER_H_