cc: Separate the priority from the tile and put in new PrioritizedTile

cc/resources/tiling_set_raster_queue_required.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_RASTER_QUEUE_REQUIRED_H_
 #define CC_RESOURCES_TILING_SET_RASTER_QUEUE_REQUIRED_H_
 
 #include "cc/base/cc_export.h"
 #include "cc/resources/picture_layer_tiling_set.h"
 #include "cc/resources/raster_tile_priority_queue.h"
 #include "cc/resources/tile.h"
 
 namespace cc {
 
 // This queue only returns tiles that are required for either activation or
 // draw, as specified by RasterTilePriorityQueue::Type passed in the
 // constructor.
 class CC_EXPORT TilingSetRasterQueueRequired {
  public:
   TilingSetRasterQueueRequired(PictureLayerTilingSet* tiling_set,
                                RasterTilePriorityQueue::Type type);
   ~TilingSetRasterQueueRequired();
 
-  Tile* Top();
-  const Tile* Top() const;
+  const PrioritizedTile& Top() const;
   void Pop();
   bool IsEmpty() const;
 
  private:
   // This iterator will return all tiles that are in the NOW bin on the given
   // tiling. The queue can then use these tiles and further filter them based on
   // whether they are required or not.
   class TilingIterator {
    public:
     TilingIterator();
     explicit TilingIterator(PictureLayerTiling* tiling,
                             TilingData* tiling_data,
                             const gfx::Rect& rect);
     ~TilingIterator();
 
-    bool done() const { return current_tile_ == nullptr; }
-    const Tile* operator*() const { return current_tile_; }
-    Tile* operator*() { return current_tile_; }
+    bool done() const { return !current_tile_.tile(); }
+    const PrioritizedTile& operator*() const { return current_tile_; }
     TilingIterator& operator++();
 
    private:
     PictureLayerTiling* tiling_;
     TilingData* tiling_data_;
 
-    Tile* current_tile_;
+    PrioritizedTile current_tile_;
     TilingData::Iterator visible_iterator_;
   };
 
-  bool IsTileRequired(const Tile* tile) const;
+  bool IsTileRequired(const PrioritizedTile& prioritized_tile) const;
 
   TilingIterator iterator_;
   RasterTilePriorityQueue::Type type_;
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_TILING_SET_RASTER_QUEUE_REQUIRED_H_