cc: Move (partially) the predecode image tracking to ImageManager.

cc/tiles/tile_manager.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_TILES_TILE_MANAGER_H_
 #define CC_TILES_TILE_MANAGER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 320 matching lines @@
   Signals signals_;
 
   UniqueNotifier signals_check_notifier_;
 
   bool has_scheduled_tile_tasks_;
 
   uint64_t prepare_tiles_count_;
   uint64_t next_tile_id_;
 
   std::unordered_map<Tile::Id, std::vector<DrawImage>> scheduled_draw_images_;
-  std::vector<DrawImage> locked_images_;
   std::vector<scoped_refptr<TileTask>> locked_image_tasks_;
 
   base::WeakPtrFactory<TileManager> task_set_finished_weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TileManager);
 };
 
 }  // namespace cc
 
 #endif  // CC_TILES_TILE_MANAGER_H_