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

cc/output/software_output_device.cc

 // 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.
 
 #include "cc/output/software_output_device.h"
 
 #include "base/logging.h"
 #include "cc/output/software_frame_data.h"
 #include "third_party/skia/include/core/SkBitmapDevice.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "ui/gfx/skia_util.h"
 #include "ui/gfx/vsync_provider.h"
 
 namespace cc {
 
 SoftwareOutputDevice::SoftwareOutputDevice() {}
 
 SoftwareOutputDevice::~SoftwareOutputDevice() {}
 
 void SoftwareOutputDevice::Resize(gfx::Size viewport_size) {
   if (viewport_size_ == viewport_size)
     return;
 
   viewport_size_ = viewport_size;
   device_ = skia::AdoptRef(new SkBitmapDevice(SkBitmap::kARGB_8888_Config,
       viewport_size.width(), viewport_size.height(), true));
   canvas_ = skia::AdoptRef(new SkCanvas(device_.get()));
 }
 
-SkCanvas* SoftwareOutputDevice::BeginPaint(gfx::Rect damage_rect) {
+SkCanvas* SoftwareOutputDevice::BeginPaint(const gfx::Rect& damage_rect) {
   DCHECK(device_);
   damage_rect_ = damage_rect;
   return canvas_.get();
 }
 
 void SoftwareOutputDevice::EndPaint(SoftwareFrameData* frame_data) {
   DCHECK(frame_data);
   frame_data->id = 0;
   frame_data->size = viewport_size_;
   frame_data->damage_rect = damage_rect_;
   frame_data->handle = base::SharedMemory::NULLHandle();
 }
 
 void SoftwareOutputDevice::CopyToBitmap(
-    gfx::Rect rect, SkBitmap* output) {
+    const gfx::Rect& rect, SkBitmap* output) {
   DCHECK(device_);
   const SkBitmap& bitmap = device_->accessBitmap(false);
   bitmap.extractSubset(output, gfx::RectToSkIRect(rect));
 }
 
 void SoftwareOutputDevice::Scroll(
-    gfx::Vector2d delta, gfx::Rect clip_rect) {
+    gfx::Vector2d delta, const gfx::Rect& clip_rect) {
   NOTIMPLEMENTED();
 }
 
 void SoftwareOutputDevice::ReclaimSoftwareFrame(unsigned id) {
   NOTIMPLEMENTED();
 }
 
 gfx::VSyncProvider* SoftwareOutputDevice::GetVSyncProvider() {
   return vsync_provider_.get();
 }
 
 }  // namespace cc