Revert of cc: Remove tile sharing from tilings.

cc/resources/tiling_set_eviction_queue.h

 // Copyright 2014 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_TILING_SET_EVICTION_QUEUE_H_
 #define CC_RESOURCES_TILING_SET_EVICTION_QUEUE_H_
 
 #include <vector>
 
 #include "cc/base/cc_export.h"
 #include "cc/resources/picture_layer_tiling_set.h"
 
 namespace cc {
 
 // This eviction queue returned tiles from all tilings in a tiling set in
 // the order in which the tiles should be evicted. It can be thought of as the
 // following:
 //  for all phases:
 //    for all ordered tilings:
 //      yield the next tile for the given phase from the given tiling
 //
 // Phases are the following (in order in which they are processed):
 // EVENTUALLY_RECT - Tiles in the eventually region of the tiling.
 // SOON_BORDER_RECT - Tiles in the prepainting skirt of the tiling.
 // SKEWPORT_RECT - Tiles in the skewport of the tiling.
-// PENDING_VISIBLE_RECT - Tiles that will be visible upon activation, not
-//     required for activation.
-// PENDING_VISIBLE_RECT_REQUIRED_FOR_ACTIVATION - Tiles that will be visible
-//     upon activation, required for activation.
 // VISIBLE_RECT_OCCLUDED - Occluded, not required for activation, visible tiles.
 // VISIBLE_RECT_UNOCCLUDED - Unoccluded, not required for activation, visible
 //     tiles.
 // VISIBLE_RECT_REQUIRED_FOR_ACTIVATION_OCCLUDED - Occluded, but required for
 //     activation, visible tiles. This can happen when an active tree tile is
 //     occluded, but is not occluded on the pending tree (and is required for
 //     activation).
 // VISIBLE_RECT_REQUIRED_FOR_ACTIVATION_UNOCCLUDED - Unoccluded, required for
 //     activation, tiles.
 //
@@ skipping 31 matching lines @@
   Tile* Top();
   const Tile* Top() const;
   void Pop();
   bool IsEmpty() const;
 
  private:
   enum Phase {
     EVENTUALLY_RECT,
     SOON_BORDER_RECT,
     SKEWPORT_RECT,
-    PENDING_VISIBLE_RECT,
-    PENDING_VISIBLE_RECT_REQUIRED_FOR_ACTIVATION,
     VISIBLE_RECT_OCCLUDED,
     VISIBLE_RECT_UNOCCLUDED,
     VISIBLE_RECT_REQUIRED_FOR_ACTIVATION_OCCLUDED,
     VISIBLE_RECT_REQUIRED_FOR_ACTIVATION_UNOCCLUDED
   };
 
   void GenerateTilingOrder(PictureLayerTilingSet* tiling_set);
 
   // Helper base class for individual region iterators.
   class EvictionRectIterator {
    public:
     EvictionRectIterator();
     EvictionRectIterator(std::vector<PictureLayerTiling*>* tilings,
                          WhichTree tree,
-                         bool skip_shared_out_of_order_tiles,
-                         bool skip_pending_visible_rect);
+                         bool skip_shared_out_of_order_tiles);
 
     bool done() const { return !tile_; }
     Tile* operator*() const { return tile_; }
 
    protected:
     ~EvictionRectIterator() = default;
 
     template <typename TilingIteratorType>
     bool AdvanceToNextTile(TilingIteratorType* iterator);
     template <typename TilingIteratorType>
     bool GetFirstTileAndCheckIfValid(TilingIteratorType* iterator);
 
     Tile* tile_;
     std::vector<PictureLayerTiling*>* tilings_;
     WhichTree tree_;
     bool skip_shared_out_of_order_tiles_;
-    bool skip_pending_visible_rect_;
     size_t tiling_index_;
   };
 
-  class PendingVisibleTilingIterator : public EvictionRectIterator {
-   public:
-    PendingVisibleTilingIterator() = default;
-    PendingVisibleTilingIterator(std::vector<PictureLayerTiling*>* tilings,
-                                 WhichTree tree,
-                                 bool skip_shared_out_of_order_tiles,
-                                 bool return_required_for_activation_tiles);
-
-    PendingVisibleTilingIterator& operator++();
-
-   private:
-    bool TileMatchesRequiredFlags(const Tile* tile) const;
-
-    TilingData::DifferenceIterator iterator_;
-    bool return_required_for_activation_tiles_;
-  };
-
   class VisibleTilingIterator : public EvictionRectIterator {
    public:
     VisibleTilingIterator() = default;
     VisibleTilingIterator(std::vector<PictureLayerTiling*>* tilings,
                           WhichTree tree,
                           bool skip_shared_out_of_order_tiles,
                           bool return_occluded_tiles,
                           bool return_required_for_activation_tiles);
 
     VisibleTilingIterator& operator++();
@@ skipping 49 matching lines @@
 
   WhichTree tree_;
   bool skip_shared_out_of_order_tiles_;
   Phase phase_;
   Tile* current_tile_;
   std::vector<PictureLayerTiling*> tilings_;
 
   EventuallyTilingIterator eventually_iterator_;
   SoonBorderTilingIterator soon_iterator_;
   SkewportTilingIterator skewport_iterator_;
-  PendingVisibleTilingIterator pending_visible_iterator_;
   VisibleTilingIterator visible_iterator_;
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_TILING_SET_EVICTION_QUEUE_H_