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

cc/layers/layer.cc

 // Copyright 2010 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.
 
 #include "cc/layers/layer.h"
 
 #include <algorithm>
 
 #include "base/debug/trace_event.h"
 #include "base/location.h"
@@ skipping 306 matching lines @@
 }
 
 int Layer::IndexOfChild(const Layer* reference) {
   for (size_t i = 0; i < children_.size(); ++i) {
     if (children_[i].get() == reference)
       return i;
   }
   return -1;
 }
 
-void Layer::SetBounds(gfx::Size size) {
+void Layer::SetBounds(const gfx::Size& size) {
   DCHECK(IsPropertyChangeAllowed());
   if (bounds() == size)
     return;
 
   bounds_ = size;
   SetNeedsCommit();
 }
 
 Layer* Layer::RootLayer() {
   Layer* layer = this;
@@ skipping 828 matching lines @@
     clip_parent_->RemoveClipChild(this);
 
   clip_parent_ = NULL;
 }
 
 void Layer::RunMicroBenchmark(MicroBenchmark* benchmark) {
   benchmark->RunOnLayer(this);
 }
 
 }  // namespace cc