cc: Move LayerEvictionTileIterator to a separate file and make it a queue

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 "cc/base/cc_export.h"
+#include "cc/resources/picture_layer_tiling_set.h"
+
+namespace cc {
+
+class CC_EXPORT TilingSetEvictionQueue {
+ public:
+  TilingSetEvictionQueue();
+  TilingSetEvictionQueue(PictureLayerTilingSet* tiling_set,
+                         TreePriority tree_priority);
+  ~TilingSetEvictionQueue();
+
+  Tile* Top();
+  const Tile* Top() const;
+  void Pop();
+  bool IsEmpty() const;
+
+ private:
+  bool AdvanceToNextCategory();
+  bool AdvanceToNextEvictionTile();
+  bool AdvanceToNextTilingRangeType();
+  bool AdvanceToNextValidTiling();
+
+  PictureLayerTilingSet::TilingRange CurrentTilingRange() const;
+  size_t CurrentTilingIndex() const;
+
+  PictureLayerTilingSet* tiling_set_;
+  TreePriority tree_priority_;
+
+  PictureLayerTiling::EvictionCategory current_category_;
+  size_t current_tiling_index_;
+  PictureLayerTilingSet::TilingRangeType current_tiling_range_type_;
+  Tile* current_eviction_tile_;
+
+  const std::vector<Tile*>* eviction_tiles_;
+  size_t next_eviction_tile_index_;
+};
+
+}  // namespace cc
+
+#endif  // CC_RESOURCES_TILING_SET_RASTER_QUEUE_H_