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

cc/resources/layer_tiling_data.cc

 // Copyright 2011 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/layer_tiling_data.h"
 
 #include <vector>
 
 #include "base/logging.h"
 
@@ skipping 48 matching lines @@
 }
 
 scoped_ptr<LayerTilingData::Tile> LayerTilingData::TakeTile(int i, int j) {
   return tiles_.take_and_erase(std::make_pair(i, j));
 }
 
 LayerTilingData::Tile* LayerTilingData::TileAt(int i, int j) const {
   return tiles_.get(std::make_pair(i, j));
 }
 
-void LayerTilingData::ContentRectToTileIndices(gfx::Rect content_rect,
+void LayerTilingData::ContentRectToTileIndices(const gfx::Rect& content_rect,
                                                int* left,
                                                int* top,
                                                int* right,
                                                int* bottom) const {
   // An empty rect doesn't result in an empty set of tiles, so don't pass an
   // empty rect.
   // TODO(enne): Possibly we should fill a vector of tiles instead, since the
   // normal use of this function is to enumerate some tiles.
   DCHECK(!content_rect.IsEmpty());
 
   *left = tiling_data_.TileXIndexFromSrcCoord(content_rect.x());
   *top = tiling_data_.TileYIndexFromSrcCoord(content_rect.y());
   *right = tiling_data_.TileXIndexFromSrcCoord(content_rect.right() - 1);
   *bottom = tiling_data_.TileYIndexFromSrcCoord(content_rect.bottom() - 1);
 }
 
 gfx::Rect LayerTilingData::TileRect(const Tile* tile) const {
   gfx::Rect tile_rect = tiling_data_.TileBoundsWithBorder(tile->i(), tile->j());
   tile_rect.set_size(tile_size());
   return tile_rect;
 }
 
 Region LayerTilingData::OpaqueRegionInContentRect(
-    gfx::Rect content_rect) const {
+    const gfx::Rect& content_rect) const {
   if (content_rect.IsEmpty())
     return Region();
 
   Region opaque_region;
   int left, top, right, bottom;
   ContentRectToTileIndices(content_rect, &left, &top, &right, &bottom);
   for (int j = top; j <= bottom; ++j) {
     for (int i = left; i <= right; ++i) {
       Tile* tile = TileAt(i, j);
       if (!tile)
@@ skipping 22 matching lines @@
   std::vector<TileMapKey> invalid_tile_keys;
   for (TileMap::const_iterator it = tiles_.begin(); it != tiles_.end(); ++it) {
     if (it->first.first > right || it->first.second > bottom)
       invalid_tile_keys.push_back(it->first);
   }
   for (size_t i = 0; i < invalid_tile_keys.size(); ++i)
     tiles_.erase(invalid_tile_keys[i]);
 }
 
 }  // namespace cc