Pass gfx structs by const ref (gfx::Vector2d/F)

ui/compositor/layer.cc

 // Copyright (c) 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.
 
 #include "ui/compositor/layer.h"
 
 #include <algorithm>
 
 #include "base/auto_reset.h"
 #include "base/command_line.h"
@@ skipping 230 matching lines @@
       LayerAnimationElement::TRANSFORM)) {
     return animator_->GetTargetTransform();
   }
   return transform();
 }
 
 void Layer::SetBounds(const gfx::Rect& bounds) {
   GetAnimator()->SetBounds(bounds);
 }
 
-void Layer::SetSubpixelPositionOffset(const gfx::Vector2dF offset) {
+void Layer::SetSubpixelPositionOffset(const gfx::Vector2dF& offset) {
   subpixel_position_offset_ = offset;
   RecomputePosition();
 }
 
 gfx::Rect Layer::GetTargetBounds() const {
   if (animator_.get() && animator_->IsAnimatingProperty(
       LayerAnimationElement::BOUNDS)) {
     return animator_->GetTargetBounds();
   }
   return bounds_;
@@ skipping 831 matching lines @@
       children_.end(),
       std::bind2nd(std::mem_fun(&Layer::RemoveAnimatorsInTreeFromCollection),
                    collection));
 }
 
 bool Layer::IsAnimating() const {
   return animator_.get() && animator_->is_animating();
 }
 
 }  // namespace ui