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

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/command_line.h"
 #include "base/debug/trace_event.h"
@@ skipping 605 matching lines @@
     children_[i]->OnDeviceScaleFactorChanged(device_scale_factor);
   if (layer_mask_)
     layer_mask_->OnDeviceScaleFactorChanged(device_scale_factor);
 }
 
 void Layer::RequestCopyOfOutput(scoped_ptr<cc::CopyOutputRequest> request) {
   cc_layer_->RequestCopyOfOutput(request.Pass());
 }
 
 void Layer::PaintContents(SkCanvas* sk_canvas,
-                          gfx::Rect clip,
+                          const gfx::Rect& clip,
                           gfx::RectF* opaque) {
   TRACE_EVENT0("ui", "Layer::PaintContents");
   scoped_ptr<gfx::Canvas> canvas(gfx::Canvas::CreateCanvasWithoutScaling(
       sk_canvas, device_scale_factor_));
 
   bool scale_content = scale_content_;
   if (scale_content) {
     canvas->Save();
     canvas->sk_canvas()->scale(SkFloatToScalar(device_scale_factor_),
                                SkFloatToScalar(device_scale_factor_));
@@ skipping 324 matching lines @@
   cc_layer_->SetBounds(ConvertSizeToPixel(this, size));
 }
 
 void Layer::RecomputePosition() {
   cc_layer_->SetPosition(gfx::ScalePoint(
         gfx::PointF(bounds_.x(), bounds_.y()),
         device_scale_factor_));
 }
 
 }  // namespace ui