[#2] Pass gfx structs by const ref (gfx::Rect, gfx::RectF)

cc/output/copy_output_request.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_OUTPUT_COPY_OUTPUT_REQUEST_H_
 #define CC_OUTPUT_COPY_OUTPUT_REQUEST_H_
 
 #include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "cc/base/cc_export.h"
@@ skipping 28 matching lines @@
 
   ~CopyOutputRequest();
 
   bool IsEmpty() const { return result_callback_.is_null(); }
 
   bool force_bitmap_result() const { return force_bitmap_result_; }
 
   // By default copy requests copy the entire layer's subtree output. If an
   // area is given, then the intersection of this rect (in layer space) with
   // the layer's subtree output will be returned.
-  void set_area(gfx::Rect area) {
+  void set_area(const gfx::Rect& area) {
     has_area_ = true;
     area_ = area;
   }
   bool has_area() const { return has_area_; }
   gfx::Rect area() const { return area_; }
 
   // By default copy requests create a new TextureMailbox to return contents
   // in. This allows a client to provide a TextureMailbox, and the compositor
   // will place the result inside the TextureMailbox.
   void SetTextureMailbox(const TextureMailbox& texture_mailbox);
@@ skipping 17 matching lines @@
   bool has_area_;
   bool has_texture_mailbox_;
   gfx::Rect area_;
   TextureMailbox texture_mailbox_;
   CopyOutputRequestCallback result_callback_;
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_COPY_OUTPUT_REQUEST_H_