cc: Split tiling set raster queues into all and required.

cc/resources/tiling_set_raster_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_RASTER_QUEUE_H_
 #define CC_RESOURCES_TILING_SET_RASTER_QUEUE_H_
 
 #include "cc/base/cc_export.h"
-#include "cc/resources/picture_layer_tiling_set.h"
 
 namespace cc {
 
+class Tile;
 class CC_EXPORT TilingSetRasterQueue {
  public:
-  TilingSetRasterQueue();
-  TilingSetRasterQueue(PictureLayerTilingSet* tiling_set,
-                       bool prioritize_low_res);
-  ~TilingSetRasterQueue();
+  TilingSetRasterQueue() = default;
+  virtual ~TilingSetRasterQueue() = default;
 
-  Tile* Top();
-  const Tile* Top() const;
-  void Pop();
-  bool IsEmpty() const;
-
- private:
-  enum IteratorType { LOW_RES, HIGH_RES, NUM_ITERATORS };
-
-  void AdvanceToNextStage();
-
-  PictureLayerTilingSet* tiling_set_;
-
-  struct IterationStage {
-    IteratorType iterator_type;
-    TilePriority::PriorityBin tile_type;
-  };
-
-  size_t current_stage_;
-
-  // One low res stage, and three high res stages.
-  IterationStage stages_[4];
-  PictureLayerTiling::TilingRasterTileIterator iterators_[NUM_ITERATORS];
+  virtual Tile* Top() = 0;
+  virtual const Tile* Top() const = 0;
+  virtual void Pop() = 0;
+  virtual bool IsEmpty() const = 0;
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_TILING_SET_RASTER_QUEUE_H_