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

cc/output/copy_output_result.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_RESULT_H_
 #define CC_OUTPUT_COPY_OUTPUT_RESULT_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "cc/base/cc_export.h"
 #include "cc/resources/texture_mailbox.h"
 #include "ui/gfx/size.h"
 
 class SkBitmap;
 
 namespace cc {
 class SingleReleaseCallback;
 class TextureMailbox;
 
 class CC_EXPORT CopyOutputResult {
  public:
   static scoped_ptr<CopyOutputResult> CreateEmptyResult() {
     return make_scoped_ptr(new CopyOutputResult);
   }
   static scoped_ptr<CopyOutputResult> CreateBitmapResult(
       scoped_ptr<SkBitmap> bitmap) {
     return make_scoped_ptr(new CopyOutputResult(bitmap.Pass()));
   }
   static scoped_ptr<CopyOutputResult> CreateTextureResult(
-      const gfx::Size& size,
+      gfx::Size size,
       const TextureMailbox& texture_mailbox,
       scoped_ptr<SingleReleaseCallback> release_callback) {
     return make_scoped_ptr(
         new CopyOutputResult(size, texture_mailbox, release_callback.Pass()));
   }
 
   ~CopyOutputResult();
 
   bool IsEmpty() const { return !HasBitmap() && !HasTexture(); }
   bool HasBitmap() const { return !!bitmap_; }
   bool HasTexture() const { return texture_mailbox_.IsValid(); }
 
   gfx::Size size() const { return size_; }
   scoped_ptr<SkBitmap> TakeBitmap();
   void TakeTexture(TextureMailbox* texture_mailbox,
                    scoped_ptr<SingleReleaseCallback>* release_callback);
 
  private:
   CopyOutputResult();
   explicit CopyOutputResult(scoped_ptr<SkBitmap> bitmap);
-  explicit CopyOutputResult(const gfx::Size& size,
+  explicit CopyOutputResult(gfx::Size size,
                             const TextureMailbox& texture_mailbox,
                             scoped_ptr<SingleReleaseCallback> release_callback);
 
   gfx::Size size_;
   scoped_ptr<SkBitmap> bitmap_;
   TextureMailbox texture_mailbox_;
   scoped_ptr<SingleReleaseCallback> release_callback_;
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_COPY_OUTPUT_RESULT_H_