[WIP] cc: Use reverse spiral iterator in tiling eviction.

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 <set>
 #include <utility>
 #include <vector>
@@ skipping 106 matching lines @@
     Tile* current_tile_;
     TilingData::Iterator visible_iterator_;
     TilingData::SpiralDifferenceIterator spiral_iterator_;
   };
 
   class CC_EXPORT TilingEvictionTileIterator {
    public:
     TilingEvictionTileIterator();
     TilingEvictionTileIterator(PictureLayerTiling* tiling,
                                TreePriority tree_priority,
-                               EvictionCategory category);
+                               EvictionCategory category,
+                               bool skip_shared_high_priority_tiles);
     ~TilingEvictionTileIterator();
 
     operator bool() const;
     const Tile* operator*() const;
     Tile* operator*();
     TilingEvictionTileIterator& operator++();
 
    private:
-    const std::vector<Tile*>* eviction_tiles_;
-    size_t current_eviction_tiles_index_;
+    void AdvanceEventually(bool* skipped_tiles);
+    void AdvanceSoon();
+    void AdvanceNow();
+    bool PrepareTileUnlessReturnedByTwin(Tile* tile) const;
+
+    PictureLayerTiling* tiling_;
+    TreePriority tree_priority_;
+    EvictionCategory eviction_category_;
+
+    bool processing_soon_border_rect_;
+    bool skip_shared_high_priority_tiles_;
+    std::vector<Tile*> unoccluded_now_tiles_;
+    size_t unoccluded_now_tiles_index_;
+
+    Tile* current_tile_;
+
+    TilingData::Iterator visible_iterator_;
+    TilingData::ReverseSpiralDifferenceIterator spiral_iterator_;
   };
 
   ~PictureLayerTiling();
 
   // Create a tiling with no tiles.  CreateTiles must be called to add some.
   static scoped_ptr<PictureLayerTiling> Create(
       float contents_scale,
       const gfx::Size& layer_bounds,
       PictureLayerTilingClient* client);
   gfx::Size layer_bounds() const { return layer_bounds_; }
@@ skipping 167 matching lines @@
   bool RemoveTileAt(int i, int j, PictureLayerTiling* recycled_twin);
 
   // Computes a skewport. The calculation extrapolates the last visible
   // rect and the current visible rect to expand the skewport to where it
   // would be in |skewport_target_time| seconds. Note that the skewport
   // is guaranteed to contain the current visible rect.
   gfx::Rect ComputeSkewport(double current_frame_time_in_seconds,
                             const gfx::Rect& visible_rect_in_content_space)
       const;
 
-  void UpdateEvictionCacheIfNeeded(TreePriority tree_priority);
-  const std::vector<Tile*>* GetEvictionTiles(TreePriority tree_priority,
-                                             EvictionCategory category);
-
   void Invalidate(const Region& layer_region);
 
   void DoInvalidate(const Region& layer_region,
                     bool recreate_invalidated_tiles);
 
   void UpdateTileAndTwinPriority(Tile* tile) const;
   void UpdateTilePriority(Tile* tile) const;
 
   // Given properties.
   float contents_scale_;
@@ skipping 20 matching lines @@
   gfx::Rect current_soon_border_rect_;
   gfx::Rect current_eventually_rect_;
 
   bool has_visible_rect_tiles_;
   bool has_skewport_rect_tiles_;
   bool has_soon_border_rect_tiles_;
   bool has_eventually_rect_tiles_;
 
   Occlusion current_occlusion_in_layer_space_;
 
-  // TODO(reveman): Remove this in favour of an array of eviction_tiles_ when we
-  // change all enums to have a consistent way of getting the count/last
-  // element.
-  std::vector<Tile*> eviction_tiles_now_;
-  std::vector<Tile*> eviction_tiles_now_and_required_for_activation_;
-  std::vector<Tile*> eviction_tiles_soon_;
-  std::vector<Tile*> eviction_tiles_soon_and_required_for_activation_;
-  std::vector<Tile*> eviction_tiles_eventually_;
-  std::vector<Tile*> eviction_tiles_eventually_and_required_for_activation_;
-
-  bool eviction_tiles_cache_valid_;
-  TreePriority eviction_cache_tree_priority_;
-
  private:
   DISALLOW_ASSIGN(PictureLayerTiling);
 
   RectExpansionCache expansion_cache_;
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_PICTURE_LAYER_TILING_H_