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

cc/layers/picture_layer_impl.h

 // 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.
 
 #ifndef CC_LAYERS_PICTURE_LAYER_IMPL_H_
 #define CC_LAYERS_PICTURE_LAYER_IMPL_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 35 matching lines @@
   virtual void CalculateContentsScale(float ideal_contents_scale,
                                       float device_scale_factor,
                                       float page_scale_factor,
                                       bool animating_transform_to_screen,
                                       float* contents_scale_x,
                                       float* contents_scale_y,
                                       gfx::Size* content_bounds) OVERRIDE;
   virtual skia::RefPtr<SkPicture> GetPicture() OVERRIDE;
 
   // PictureLayerTilingClient overrides.
-  virtual scoped_refptr<Tile> CreateTile(PictureLayerTiling* tiling,
-                                         gfx::Rect content_rect) OVERRIDE;
+  virtual scoped_refptr<Tile> CreateTile(
+    PictureLayerTiling* tiling,
+    const gfx::Rect& content_rect) OVERRIDE;
   virtual void UpdatePile(Tile* tile) OVERRIDE;
   virtual gfx::Size CalculateTileSize(
       gfx::Size content_bounds) const OVERRIDE;
   virtual const Region* GetInvalidation() OVERRIDE;
   virtual const PictureLayerTiling* GetTwinTiling(
       const PictureLayerTiling* tiling) const OVERRIDE;
 
   // PushPropertiesTo active tree => pending tree.
   void SyncTiling(const PictureLayerTiling* tiling);
 
@@ skipping 25 matching lines @@
       std::vector<PictureLayerTiling*> used_tilings);
   float MinimumContentsScale() const;
   float SnappedContentsScale(float new_contents_scale);
   void UpdateLCDTextStatus(bool new_status);
   void ResetRasterScale();
   void MarkVisibleResourcesAsRequired() const;
   bool MarkVisibleTilesAsRequired(
       PictureLayerTiling* tiling,
       const PictureLayerTiling* optional_twin_tiling,
       float contents_scale,
-      gfx::Rect rect,
+      const gfx::Rect& rect,
       const Region& missing_region) const;
 
   void DoPostCommitInitializationIfNeeded() {
     if (needs_post_commit_initialization_)
       DoPostCommitInitialization();
   }
   void DoPostCommitInitialization();
 
   bool CanHaveTilings() const;
   bool CanHaveTilingWithScale(float contents_scale) const;
@@ skipping 33 matching lines @@
   bool should_update_tile_priorities_;
   bool should_use_gpu_rasterization_;
 
   friend class PictureLayer;
   DISALLOW_COPY_AND_ASSIGN(PictureLayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_PICTURE_LAYER_IMPL_H_