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

cc/layers/io_surface_layer_impl.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_IO_SURFACE_LAYER_IMPL_H_
 #define CC_LAYERS_IO_SURFACE_LAYER_IMPL_H_
 
 #include <string>
 
 #include "cc/base/cc_export.h"
 #include "cc/layers/layer_impl.h"
 #include "ui/gfx/size.h"
 
 namespace cc {
 
 class CC_EXPORT IOSurfaceLayerImpl : public LayerImpl {
  public:
   static scoped_ptr<IOSurfaceLayerImpl> Create(LayerTreeImpl* tree_impl,
                                                int id) {
     return make_scoped_ptr(new IOSurfaceLayerImpl(tree_impl, id));
   }
   virtual ~IOSurfaceLayerImpl();
 
-  void SetIOSurfaceProperties(unsigned io_surface_id, gfx::Size size);
+  void SetIOSurfaceProperties(unsigned io_surface_id, const gfx::Size& size);
 
   virtual scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl)
       OVERRIDE;
   virtual void PushPropertiesTo(LayerImpl* layer_tree_impl) OVERRIDE;
 
   virtual void AppendQuads(QuadSink* quad_sink,
                            AppendQuadsData* append_quads_data) OVERRIDE;
 
   virtual bool WillDraw(DrawMode draw_mode,
                         ResourceProvider* resource_provider) OVERRIDE;
@@ skipping 11 matching lines @@
   bool io_surface_changed_;
   unsigned io_surface_texture_id_;
   unsigned io_surface_resource_id_;
 
   DISALLOW_COPY_AND_ASSIGN(IOSurfaceLayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_IO_SURFACE_LAYER_IMPL_H_