cc: Rasterize cheap tiles immediately

cc/raster_worker_pool.cc

 // 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.
 
 #include "cc/raster_worker_pool.h"
 
 #include "cc/picture_pile_impl.h"
 
 namespace cc {
 
 namespace {
 
 class RasterWorkerPoolTaskImpl : public internal::WorkerPoolTask {
  public:
   RasterWorkerPoolTaskImpl(PicturePileImpl* picture_pile,
                            const RasterWorkerPool::RasterCallback& task,
                            const base::Closure& reply)
       : internal::WorkerPoolTask(reply),
         picture_pile_(picture_pile),
         task_(task) {
     DCHECK(picture_pile_);
   }
 
+  virtual void WillRunOnThread(base::Thread* thread) OVERRIDE {
+    picture_pile_ = picture_pile_->GetCloneForDrawingOnThread(thread);
+  }
+
   virtual void Run(RenderingStats* rendering_stats) OVERRIDE {
     task_.Run(picture_pile_.get(), rendering_stats);
     base::subtle::Release_Store(&completed_, 1);
   }
 
  private:
   scoped_refptr<PicturePileImpl> picture_pile_;
   RasterWorkerPool::RasterCallback task_;
 };
 
 }  // namespace
 
 RasterWorkerPool::RasterWorkerPool(
     WorkerPoolClient* client, size_t num_threads)
     : WorkerPool(client, num_threads) {
 }
 
 RasterWorkerPool::~RasterWorkerPool() {
 }
 
 void RasterWorkerPool::PostRasterTaskAndReply(PicturePileImpl* picture_pile,
+                                              bool is_cheap,
                                               const RasterCallback& task,
                                               const base::Closure& reply) {
-  Worker* worker = GetWorkerForNextTask();
-
-  scoped_refptr<PicturePileImpl> picture_pile_clone =
-      picture_pile->GetCloneForDrawingOnThread(worker);
-
-  worker->PostTask(
+  PostTask(
       make_scoped_ptr(new RasterWorkerPoolTaskImpl(
-                          picture_pile_clone.get(),
+                          picture_pile,
                           task,
-                          reply)).PassAs<internal::WorkerPoolTask>());
+                          reply)).PassAs<internal::WorkerPoolTask>(),
+                      is_cheap);
 }
 
 }  // namespace cc