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

cc/layers/tiled_layer.h

 // 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.
 
 #ifndef CC_LAYERS_TILED_LAYER_H_
 #define CC_LAYERS_TILED_LAYER_H_
 
 #include "cc/base/cc_export.h"
 #include "cc/layers/contents_scaling_layer.h"
 #include "cc/resources/layer_tiling_data.h"
@@ skipping 39 matching lines @@
   void SetTextureFormat(ResourceFormat texture_format) {
     texture_format_ = texture_format;
   }
   void SetBorderTexelOption(LayerTilingData::BorderTexelOption option);
   size_t NumPaintedTiles() { return tiler_->tiles().size(); }
 
   virtual LayerUpdater* Updater() const = 0;
   virtual void CreateUpdaterIfNeeded() = 0;
 
   // Set invalidations to be potentially repainted during Update().
-  void InvalidateContentRect(gfx::Rect content_rect);
+  void InvalidateContentRect(const gfx::Rect& content_rect);
 
   // Reset state on tiles that will be used for updating the layer.
   void ResetUpdateState();
 
   // After preparing an update, returns true if more painting is needed.
   bool NeedsIdlePaint();
   gfx::Rect IdlePaintRect();
 
   bool SkipsDraw() const { return skips_draw_; }
 
@@ skipping 32 matching lines @@
                             int right,
                             int bottom,
                             bool ignore_occlusions);
   void MarkTilesForUpdate(gfx::Rect* update_rect,
                           gfx::Rect* paint_rect,
                           int left,
                           int top,
                           int right,
                           int bottom,
                           bool ignore_occlusions);
-  void UpdateTileTextures(gfx::Rect update_rect,
-                          gfx::Rect paint_rect,
+  void UpdateTileTextures(const gfx::Rect& update_rect,
+                          const gfx::Rect& paint_rect,
                           int left,
                           int top,
                           int right,
                           int bottom,
                           ResourceUpdateQueue* queue,
                           const OcclusionTracker* occlusion);
   void UpdateScrollPrediction();
 
   UpdatableTile* TileAt(int i, int j) const;
   UpdatableTile* CreateTile(int i, int j);
@@ skipping 12 matching lines @@
 
   TilingOption tiling_option_;
   scoped_ptr<LayerTilingData> tiler_;
 
   DISALLOW_COPY_AND_ASSIGN(TiledLayer);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_TILED_LAYER_H_