Makes tile-creation lazy

cc/resources/picture_layer_tiling.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_H_
 #define CC_RESOURCES_PICTURE_LAYER_TILING_H_
 
 #include <utility>
 #include <vector>
 
@@ skipping 14 matching lines @@
 
 class PictureLayerTilingClient {
  public:
   // Create a tile at the given content_rect (in the contents scale of the
   // tiling) This might return null if the client cannot create such a tile.
   virtual scoped_refptr<Tile> CreateTile(
     PictureLayerTiling* tiling,
     gfx::Rect content_rect) = 0;
   virtual void UpdatePile(Tile* tile) = 0;
   virtual gfx::Size CalculateTileSize(
-    gfx::Size current_tile_size,
     gfx::Size content_bounds) = 0;
+  virtual const Region* GetInvalidation() = 0;
+  virtual const PictureLayerTiling* GetTwinTiling(
+      const PictureLayerTiling* tiling) = 0;
 
  protected:
   virtual ~PictureLayerTilingClient() {}
 };
 
 class CC_EXPORT PictureLayerTiling {
  public:
   ~PictureLayerTiling();
 
   // Create a tiling with no tiles.  CreateTiles must be called to add some.
-  static scoped_ptr<PictureLayerTiling> Create(float contents_scale);
-  scoped_ptr<PictureLayerTiling> Clone() const;
-
+  static scoped_ptr<PictureLayerTiling> Create(
+      float contents_scale,
+      gfx::Size layer_bounds,
+      PictureLayerTilingClient* client);
+  scoped_ptr<PictureLayerTiling> Clone(gfx::Size layer_bounds,
+                                       PictureLayerTilingClient* client) const;
   gfx::Size layer_bounds() const { return layer_bounds_; }
-  void SetLayerBounds(gfx::Size layer_bounds);
-  void Invalidate(const Region& layer_invalidation);
   void InvalidateTilesWithText();
 
   // Add any tiles that intersect with |layer_rect|.  If any tiles already
   // exist, then this leaves them as-is.
-  void CreateTilesFromLayerRect(gfx::Rect layer_rect);
 
   void SetClient(PictureLayerTilingClient* client);
   void set_resolution(TileResolution resolution) { resolution_ = resolution; }
   TileResolution resolution() const { return resolution_; }
 
   gfx::Rect ContentRect() const;
   gfx::SizeF ContentSizeF() const;
   float contents_scale() const { return contents_scale_; }
 
+  void CreateAllTilesForTesting() {
+    SetLiveTilesRect(gfx::Rect(tiling_data_.total_size()));
+  }
+
   std::vector<Tile*> AllTilesForTesting() const {
     std::vector<Tile*> all_tiles;
     for (TileMap::const_iterator it = tiles_.begin();
          it != tiles_.end(); ++it)
       all_tiles.push_back(it->second);
     return all_tiles;
   }
 
-  static gfx::Rect ExpandRectEquallyToAreaBoundedBy(
-      gfx::Rect starting_rect,
-      int64 target_area,
-      gfx::Rect bounding_rect);
-
   // Iterate over all tiles to fill content_rect.  Even if tiles are invalid
   // (i.e. no valid resource) this tiling should still iterate over them.
   // The union of all geometry_rect calls for each element iterated over should
   // exactly equal content_rect and no two geometry_rects should intersect.
   class CC_EXPORT CoverageIterator {
    public:
     CoverageIterator();
     CoverageIterator(const PictureLayerTiling* tiling,
         float dest_scale,
         gfx::Rect rect);
@@ skipping 28 matching lines @@
     int left_;
     int top_;
     int right_;
     int bottom_;
 
     friend class PictureLayerTiling;
   };
 
   Region OpaqueRegionInContentRect(const gfx::Rect&) const;
 
-  void Reset() { return tiles_.clear(); }
+  void Reset();
 
   void UpdateTilePriorities(
       WhichTree tree,
       gfx::Size device_viewport,
       const gfx::RectF& viewport_in_layer_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,
       int current_source_frame_number,
       double current_frame_time,
       bool store_screen_space_quads_on_tiles,
       size_t max_tiles_for_interest_area);
 
   // Copies the src_tree priority into the dst_tree priority for all tiles.
   // The src_tree priority is reset to the lowest priority possible.  This
   // also updates the pile on each tile to be the current client's pile.
   void DidBecomeActive();
 
   scoped_ptr<base::Value> AsValue() const;
 
+  static gfx::Rect ExpandRectEquallyToAreaBoundedBy(
+      gfx::Rect starting_rect,
+      int64 target_area,
+      gfx::Rect bounding_rect);
+
  protected:
   typedef std::pair<int, int> TileMapKey;
   typedef base::hash_map<TileMapKey, scoped_refptr<Tile> > TileMap;
 
-  explicit PictureLayerTiling(float contents_scale);
+  PictureLayerTiling(float contents_scale,
+                     gfx::Size layer_bounds,
+                     PictureLayerTilingClient* client);
+  void SetLiveTilesRect(gfx::Rect live_tiles_rect);
+  void CreateTile(int i, int j);
   Tile* TileAt(int, int) const;
-  void CreateTilesFromContentRect(gfx::Rect layer_rect);
-  void CreateTile(int i, int j);
 
-  PictureLayerTilingClient* client_;
+  // Given properties.
   float contents_scale_;
   gfx::Size layer_bounds_;
-  gfx::Rect last_prioritized_rect_;
-  // It is not legal to have a NULL tile in the tiles_ map.
-  TileMap tiles_;
+  TileResolution resolution_;
+  PictureLayerTilingClient* client_;
+
+  // Internal data.
   TilingData tiling_data_;
-  TileResolution resolution_;
+  TileMap tiles_;  // It is not legal to have a NULL tile in the tiles_ map.
+  gfx::Rect live_tiles_rect_;
+
+  // State saved for computing velocities based upon finite differences.
   int last_source_frame_number_;
   double last_impl_frame_time_;
 
   friend class CoverageIterator;
 
  private:
   DISALLOW_ASSIGN(PictureLayerTiling);
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_PICTURE_LAYER_TILING_H_