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

cc/layers/content_layer.h

 // Copyright 2010 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_CONTENT_LAYER_H_
 #define CC_LAYERS_CONTENT_LAYER_H_
 
 #include "base/basictypes.h"
 #include "cc/base/cc_export.h"
 #include "cc/layers/tiled_layer.h"
 #include "cc/resources/layer_painter.h"
 
 class SkCanvas;
 
 namespace cc {
 
 class ContentLayerClient;
 class ContentLayerUpdater;
 
 class CC_EXPORT ContentLayerPainter : public LayerPainter {
  public:
   static scoped_ptr<ContentLayerPainter> Create(ContentLayerClient* client);
 
   virtual void Paint(SkCanvas* canvas,
-                     gfx::Rect content_rect,
+                     const gfx::Rect& content_rect,
                      gfx::RectF* opaque) OVERRIDE;
 
  private:
   explicit ContentLayerPainter(ContentLayerClient* client);
 
   ContentLayerClient* client_;
 
   DISALLOW_COPY_AND_ASSIGN(ContentLayerPainter);
 };
 
@@ skipping 35 matching lines @@
 
   ContentLayerClient* client_;
   scoped_refptr<ContentLayerUpdater> updater_;
   bool can_use_lcd_text_last_frame_;
 
   DISALLOW_COPY_AND_ASSIGN(ContentLayer);
 };
 
 }  // namespace cc
 #endif  // CC_LAYERS_CONTENT_LAYER_H_