[#7] Pass gfx structs by const ref (gfx::Size)

cc/layers/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_LAYER_H_
 #define CC_LAYERS_LAYER_H_
 
 #include <set>
 #include <string>
 
@@ skipping 98 matching lines @@
   float anchor_point_z() const { return anchor_point_z_; }
 
   virtual void SetBackgroundColor(SkColor background_color);
   SkColor background_color() const { return background_color_; }
   // If contents_opaque(), return an opaque color else return a
   // non-opaque color.  Tries to return background_color(), if possible.
   SkColor SafeOpaqueBackgroundColor() const;
 
   // A layer's bounds are in logical, non-page-scaled pixels (however, the
   // root layer's bounds are in physical pixels).
-  void SetBounds(gfx::Size bounds);
+  void SetBounds(const gfx::Size& bounds);
   gfx::Size bounds() const { return bounds_; }
 
   void SetMasksToBounds(bool masks_to_bounds);
   bool masks_to_bounds() const { return masks_to_bounds_; }
 
   void SetMaskLayer(Layer* mask_layer);
   Layer* mask_layer() { return mask_layer_.get(); }
   const Layer* mask_layer() const { return mask_layer_.get(); }
 
   virtual void SetNeedsDisplayRect(const gfx::RectF& dirty_rect);
@@ skipping 487 matching lines @@
   DrawProperties<Layer> draw_properties_;
 
   PaintProperties paint_properties_;
 
   DISALLOW_COPY_AND_ASSIGN(Layer);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_H_