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

cc/test/pixel_test_software_output_device.h

 // Copyright 2013 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_TEST_PIXEL_TEST_SOFTWARE_OUTPUT_DEVICE_H_
 #define CC_TEST_PIXEL_TEST_SOFTWARE_OUTPUT_DEVICE_H_
 
 #include "cc/output/software_output_device.h"
 
 namespace cc {
 
 class PixelTestSoftwareOutputDevice : public SoftwareOutputDevice {
  public:
-  virtual void Resize(const gfx::Size& size) OVERRIDE;
+  virtual void Resize(gfx::Size size) OVERRIDE;
 
-  void set_surface_expansion_size(const gfx::Size& surface_expansion_size) {
+  void set_surface_expansion_size(gfx::Size surface_expansion_size) {
     surface_expansion_size_ = surface_expansion_size;
   }
 
  private:
   gfx::Size surface_expansion_size_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_PIXEL_TEST_SOFTWARE_OUTPUT_DEVICE_H_