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

cc/test/fake_content_layer_client.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_TEST_FAKE_CONTENT_LAYER_CLIENT_H_
 #define CC_TEST_FAKE_CONTENT_LAYER_CLIENT_H_
 
 #include <utility>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "cc/layers/content_layer_client.h"
 #include "third_party/skia/include/core/SkPaint.h"
 #include "ui/gfx/rect.h"
 
 namespace cc {
 
 class FakeContentLayerClient : public cc::ContentLayerClient {
  public:
   FakeContentLayerClient();
   virtual ~FakeContentLayerClient();
 
   virtual void PaintContents(SkCanvas* canvas,
                              gfx::Rect rect,
                              gfx::RectF* opaque_rect) OVERRIDE;
   virtual void DidChangeLayerCanUseLCDText() OVERRIDE {}
 
   void set_paint_all_opaque(bool opaque) { paint_all_opaque_ = opaque; }
 
-  void add_draw_rect(const gfx::Rect& rect, const SkPaint& paint) {
+  void add_draw_rect(gfx::Rect rect, const SkPaint& paint) {
     draw_rects_.push_back(std::make_pair(rect, paint));
   }
 
  private:
   typedef std::vector<std::pair<gfx::Rect, SkPaint> > RectPaintVector;
 
   bool paint_all_opaque_;
   RectPaintVector draw_rects_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_FAKE_CONTENT_LAYER_CLIENT_H_