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

cc/output/copy_output_result.h

Index: cc/output/copy_output_result.h
diff --git a/cc/output/copy_output_result.h b/cc/output/copy_output_result.h
index c2f011d20fc41aaeeeff2594634c5447656038ee..b4806581c3fa1b510df0764ac2696fca5d11a710 100644
--- a/cc/output/copy_output_result.h
+++ b/cc/output/copy_output_result.h
@@ -26,7 +26,7 @@ class CC_EXPORT CopyOutputResult {
     return make_scoped_ptr(new CopyOutputResult(bitmap.Pass()));
   }
   static scoped_ptr<CopyOutputResult> CreateTextureResult(
-      gfx::Size size,
+      const gfx::Size& size,
       const TextureMailbox& texture_mailbox,
       scoped_ptr<SingleReleaseCallback> release_callback) {
     return make_scoped_ptr(
@@ -47,7 +47,7 @@ class CC_EXPORT CopyOutputResult {
  private:
   CopyOutputResult();
   explicit CopyOutputResult(scoped_ptr<SkBitmap> bitmap);
-  explicit CopyOutputResult(gfx::Size size,
+  explicit CopyOutputResult(const gfx::Size& size,
                             const TextureMailbox& texture_mailbox,
                             scoped_ptr<SingleReleaseCallback> release_callback);