Added a vector to TileManager to explicitly track live or allocated tiles.

cc/tile.h

 // Copyright 2012 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_TILE_H_
 #define CC_TILE_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
@@ skipping 77 matching lines @@
   ~Tile();
 
   TileManager* tile_manager_;
   scoped_refptr<PicturePileImpl> picture_pile_;
   gfx::Rect tile_size_;
   GLenum format_;
   gfx::Rect content_rect_;
   float contents_scale_;
   gfx::Rect opaque_rect_;
 
-  TilePriority priority_[2];
+  TilePriority priority_[NUM_BIN_PRIORITIES];
   ManagedTileState managed_state_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TILE_H_