Update from https://crrev.com/309717

cc/resources/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_RESOURCES_TILE_MANAGER_H_
 #define CC_RESOURCES_TILE_MANAGER_H_
 
 #include <deque>
 #include <queue>
 #include <set>
@@ skipping 223 matching lines @@
                                                 MemoryUsage* usage);
   bool FreeTileResourcesWithLowerPriorityUntilUsageIsWithinLimit(
       const MemoryUsage& limit,
       const TilePriority& oother_priority,
       MemoryUsage* usage);
   bool TilePriorityViolatesMemoryPolicy(const TilePriority& priority);
   bool IsReadyToActivate() const;
   bool IsReadyToDraw() const;
   void CheckIfReadyToActivate();
   void CheckIfReadyToDraw();
+  void CheckIfMoreTilesNeedToBePrepared();
 
   TileManagerClient* client_;
   scoped_refptr<base::SequencedTaskRunner> task_runner_;
   ResourcePool* resource_pool_;
   TileTaskRunner* tile_task_runner_;
   GlobalStateThatImpactsTilePriority global_state_;
   size_t scheduled_raster_task_limit_;
 
   typedef base::hash_map<Tile::Id, Tile*> TileMap;
   TileMap tiles_;
@@ skipping 18 matching lines @@
 
   ResourceFormat resource_format_;
 
   // Queue used when scheduling raster tasks.
   TileTaskQueue raster_queue_;
 
   std::vector<scoped_refptr<RasterTask>> orphan_raster_tasks_;
 
   UniqueNotifier ready_to_activate_check_notifier_;
   UniqueNotifier ready_to_draw_check_notifier_;
+  UniqueNotifier more_tiles_need_prepare_check_notifier_;
 
   RasterTilePriorityQueue raster_priority_queue_;
   EvictionTilePriorityQueue eviction_priority_queue_;
   bool eviction_priority_queue_is_up_to_date_;
 
   bool did_notify_ready_to_activate_;
   bool did_notify_ready_to_draw_;
 
   DISALLOW_COPY_AND_ASSIGN(TileManager);
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_TILE_MANAGER_H_