Makes tile-creation lazy

cc/resources/picture_layer_tiling_set.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_RESOURCES_PICTURE_LAYER_TILING_SET_H_
 #define CC_RESOURCES_PICTURE_LAYER_TILING_SET_H_
 
 #include "cc/base/region.h"
 #include "cc/base/scoped_ptr_vector.h"
 #include "cc/resources/picture_layer_tiling.h"
 #include "ui/gfx/size.h"
 
 namespace cc {
 
 class CC_EXPORT PictureLayerTilingSet {
  public:
-  explicit PictureLayerTilingSet(PictureLayerTilingClient* client);
+  PictureLayerTilingSet(PictureLayerTilingClient* client,
+                        gfx::Size layer_bounds);
   ~PictureLayerTilingSet();
 
   void SetClient(PictureLayerTilingClient* client);
 
   // Shallow copies all data (except client and bounds from other).
   void CloneAll(
      const PictureLayerTilingSet& other,
-     const Region& invalidation,
      float minimum_contents_scale);
-  void Clone(const PictureLayerTiling* tiling, const Region& invalidation);
+  void Clone(const PictureLayerTiling* tiling);
 
-  void SetLayerBounds(gfx::Size layer_bounds);
-  gfx::Size LayerBounds() const;
-
-  void Invalidate(const Region& layer_invalidation);
+  gfx::Size layer_bounds() const { return layer_bounds_; }
 
   PictureLayerTiling* AddTiling(float contents_scale);
   size_t num_tilings() const { return tilings_.size(); }
   PictureLayerTiling* tiling_at(size_t idx) { return tilings_[idx]; }
   const PictureLayerTiling* tiling_at(size_t idx) const {
     return tilings_[idx];
   }
 
   // Remove all tilings.
   void RemoveAllTilings();
 
   // Remove one tiling.
   void Remove(PictureLayerTiling* tiling);
 
   // Remove all tiles; keep all tilings.
   void RemoveAllTiles();
 
-  // For all tilings, create any tile that intersects |layer_rect|.
-  void CreateTilesFromLayerRect(gfx::Rect layer_rect);
-
   void UpdateTilePriorities(
       WhichTree tree,
       gfx::Size device_viewport,
       gfx::Rect viewport_in_content_space,
       gfx::Size last_layer_bounds,
       gfx::Size current_layer_bounds,
       float last_layer_contents_scale,
       float current_layer_contents_scale,
       const gfx::Transform& last_screen_transform,
       const gfx::Transform& current_screen_transform,
@@ skipping 55 matching lines @@
   gfx::Size layer_bounds_;
   ScopedPtrVector<PictureLayerTiling> tilings_;
 
   friend class Iterator;
   DISALLOW_COPY_AND_ASSIGN(PictureLayerTilingSet);
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_PICTURE_LAYER_TILING_SET_H_