cc: Don't pass simple well-defined classes by reference.

cc/test/fake_picture_pile_impl.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_FAKE_PICTURE_PILE_IMPL_H_
 #define CC_TEST_FAKE_PICTURE_PILE_IMPL_H_
 
 #include "base/memory/ref_counted.h"
 #include "cc/resources/picture_pile_impl.h"
 #include "cc/test/fake_content_layer_client.h"
 
 namespace cc {
 
 class FakePicturePileImpl : public PicturePileImpl {
  public:
   static scoped_refptr<FakePicturePileImpl> CreateFilledPile(
       gfx::Size tile_size,
       gfx::Size layer_bounds);
 
   static scoped_refptr<FakePicturePileImpl> CreateEmptyPile(
       gfx::Size tile_size,
       gfx::Size layer_bounds);
 
   TilingData& tiling() { return tiling_; }
 
   void AddRecordingAt(int x, int y);
 
   void RemoveRecordingAt(int x, int y);
 
-  void add_draw_rect(const gfx::Rect& rect) {
+  void add_draw_rect(gfx::Rect rect) {
     client_.add_draw_rect(rect, default_paint_);
   }
 
   void add_draw_rect_with_paint(gfx::Rect rect, const SkPaint& paint) {
     client_.add_draw_rect(rect, paint);
   }
 
   void set_default_paint(const SkPaint& paint) {
     default_paint_ = paint;
   }
 
  protected:
   FakePicturePileImpl();
   virtual ~FakePicturePileImpl();
 
   FakeContentLayerClient client_;
   SkPaint default_paint_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_FAKE_PICTURE_PILE_IMPL_H_