cc: Do not cleanup tiles with raster tasks.

cc/resources/prioritized_tile_set.h

 // Copyright 2013 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_PRIORITIZED_TILE_SET_H_
 #define CC_RESOURCES_PRIORITIZED_TILE_SET_H_
 
 #include <vector>
 
 #include "cc/base/cc_export.h"
 #include "cc/resources/managed_tile_state.h"
 
 namespace cc {
 class Tile;
 
 class CC_EXPORT PrioritizedTileSet {
  public:
   PrioritizedTileSet();
   ~PrioritizedTileSet();
 
   void InsertTile(Tile* tile, ManagedTileBin bin);
   void Clear();
+  bool IsEmpty();
 
   class CC_EXPORT Iterator {
    public:
     Iterator(PrioritizedTileSet* set, bool use_priority_ordering);
 
     ~Iterator();
 
     void DisablePriorityOrdering();
 
     Iterator& operator++();
@@ skipping 17 matching lines @@
 
   void SortBinIfNeeded(ManagedTileBin bin);
 
   std::vector<Tile*> tiles_[NUM_BINS];
   bool bin_sorted_[NUM_BINS];
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_PRIORITIZED_TILE_SET_H_