cc: Only make num_threads - 1 SkPicture clones.

cc/resources/raster_worker_pool.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_RASTER_WORKER_POOL_H_
 #define CC_RESOURCES_RASTER_WORKER_POOL_H_
 
 #include <deque>
 #include <vector>
 
@@ skipping 174 matching lines @@
 
     scoped_refptr<internal::RasterWorkerPoolTask> internal_;
   };
 
   virtual ~RasterWorkerPool();
 
   static void SetNumRasterThreads(int num_threads);
 
   static int GetNumRasterThreads();
 
+  static internal::TaskGraphRunner* GetTaskGraphRunner();
+
+  static unsigned kOnDemandRasterTaskPriority;
+  static unsigned kRasterFinishedTaskPriority;
+  static unsigned kRasterRequiredForActivationFinishedTaskPriority;
+  static unsigned kRasterTaskPriorityBase;
+
   // TODO(vmpstr): Figure out an elegant way to not pass this many parameters.
   static RasterTask CreateRasterTask(
       const Resource* resource,
       PicturePileImpl* picture_pile,
       const gfx::Rect& content_rect,
       float contents_scale,
       RasterMode raster_mode,
       TileResolution tile_resolution,
       int layer_id,
       const void* tile_id,
@@ skipping 109 matching lines @@
                                 internal::WorkerPoolTask* task,
                                 unsigned priority,
                                 size_t dependencies);
 
   static void InsertNodeForRasterTask(
       internal::TaskGraph* graph,
       internal::WorkerPoolTask* task,
       const internal::Task::Vector& decode_tasks,
       unsigned priority);
 
-  static unsigned kRasterFinishedTaskPriority;
-  static unsigned kRasterRequiredForActivationFinishedTaskPriority;
-  static unsigned kRasterTaskPriorityBase;
-
  private:
   void OnRasterFinished(const internal::WorkerPoolTask* source);
   void OnRasterRequiredForActivationFinished(
       const internal::WorkerPoolTask* source);
 
   internal::TaskGraphRunner* task_graph_runner_;
   internal::NamespaceToken namespace_token_;
   RasterWorkerPoolClient* client_;
   ResourceProvider* resource_provider_;
   ContextProvider* context_provider_;
   TaskDeque completed_gpu_raster_tasks_;
 
   scoped_refptr<internal::WorkerPoolTask> raster_finished_task_;
   scoped_refptr<internal::WorkerPoolTask>
       raster_required_for_activation_finished_task_;
   base::WeakPtrFactory<RasterWorkerPool> weak_ptr_factory_;
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_RASTER_WORKER_POOL_H_