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

cc/resources/tile_manager.cc

 // Copyright 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 "cc/resources/tile_manager.h"
 
 #include <algorithm>
 #include <limits>
 #include <string>
 
@@ skipping 951 matching lines @@
     ++resources_releasable_;
   }
 
   FreeUnusedResourcesForTile(tile);
   if (tile->priority(ACTIVE_TREE).distance_to_visible_in_pixels == 0)
     did_initialize_visible_tile_ = true;
 }
 
 scoped_refptr<Tile> TileManager::CreateTile(PicturePileImpl* picture_pile,
                                             gfx::Size tile_size,
-                                            gfx::Rect content_rect,
-                                            gfx::Rect opaque_rect,
+                                            const gfx::Rect& content_rect,
+                                            const gfx::Rect& opaque_rect,
                                             float contents_scale,
                                             int layer_id,
                                             int source_frame_number,
                                             int flags) {
   scoped_refptr<Tile> tile = make_scoped_refptr(new Tile(this,
                                                          picture_pile,
                                                          tile_size,
                                                          content_rect,
                                                          opaque_rect,
                                                          contents_scale,
                                                          layer_id,
                                                          source_frame_number,
                                                          flags));
   DCHECK(tiles_.find(tile->id()) == tiles_.end());
 
   tiles_[tile->id()] = tile;
   used_layer_counts_[tile->layer_id()]++;
   prioritized_tiles_dirty_ = true;
   return tile;
 }
 
 }  // namespace cc