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

cc/resources/picture_pile_base.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/resources/picture_pile_base.h"
 
 #include <algorithm>
 #include <set>
 #include <vector>
 
@@ skipping 170 matching lines @@
   }
 }
 
 bool PicturePileBase::HasRecordingAt(int x, int y) {
   PictureMap::const_iterator found = picture_map_.find(PictureMapKey(x, y));
   if (found == picture_map_.end())
     return false;
   return !!found->second.GetPicture();
 }
 
-bool PicturePileBase::CanRaster(float contents_scale, gfx::Rect content_rect) {
+bool PicturePileBase::CanRaster(float contents_scale,
+                                const gfx::Rect& content_rect) {
   if (tiling_.total_size().IsEmpty())
     return false;
   gfx::Rect layer_rect = gfx::ScaleToEnclosingRect(
       content_rect, 1.f / contents_scale);
   layer_rect.Intersect(gfx::Rect(tiling_.total_size()));
   return recorded_region_.Contains(layer_rect);
 }
 
 gfx::Rect PicturePileBase::PaddedRect(const PictureMapKey& key) {
   gfx::Rect tile = tiling_.TileBounds(key.first, key.second);
   return PadRect(tile);
 }
 
-gfx::Rect PicturePileBase::PadRect(gfx::Rect rect) {
+gfx::Rect PicturePileBase::PadRect(const gfx::Rect& rect) {
   gfx::Rect padded_rect = rect;
   padded_rect.Inset(
       -buffer_pixels(), -buffer_pixels(), -buffer_pixels(), -buffer_pixels());
   return padded_rect;
 }
 
 scoped_ptr<base::Value> PicturePileBase::AsValue() const {
   scoped_ptr<base::ListValue> pictures(new base::ListValue());
   gfx::Rect layer_rect(tiling_.total_size());
   std::set<void*> appended_pictures;
@@ skipping 63 matching lines @@
     info.picture_ = picture_->GetCloneForDrawingOnThread(thread_index);
   return info;
 }
 
 float PicturePileBase::PictureInfo::GetInvalidationFrequency() const {
   return invalidation_history_.count() /
          static_cast<float>(INVALIDATION_FRAMES_TRACKED);
 }
 
 }  // namespace cc