cc: Rasterize cheap tiles immediately

cc/raster_worker_pool.cc

Index: cc/raster_worker_pool.cc
diff --git a/cc/raster_worker_pool.cc b/cc/raster_worker_pool.cc
index bc6e50e7084ad8c9e94ca42afe7b098b107a7f92..c260379fedba7c5ad7ee6638c90fd6fe2cacb4ea 100644
--- a/cc/raster_worker_pool.cc
+++ b/cc/raster_worker_pool.cc
@@ -25,6 +25,10 @@ class RasterWorkerPoolTaskImpl : public internal::WorkerPoolTask {
     task_.Run(picture_pile_.get(), rendering_stats);
   }
 
+  virtual void DeferToThread(base::Thread* thread) OVERRIDE {
+    picture_pile_ = picture_pile_->GetCloneForDrawingOnThread(thread);

[reveman, 2013/02/13 22:17:36]

If we need this, I prefer if we didn't also do cloning in PostRasterTaskAndReply
below.

+  }
+
  private:
   scoped_refptr<PicturePileImpl> picture_pile_;
   RasterWorkerPool::RasterCallback task_;
@@ -40,8 +44,18 @@ RasterWorkerPool::~RasterWorkerPool() {
 }
 
 void RasterWorkerPool::PostRasterTaskAndReply(PicturePileImpl* picture_pile,
+                                              bool is_cheap,
                                               const RasterCallback& task,
                                               const base::Closure& reply) {
+  if (is_cheap && CanPostCheapTask()) {
+    PostCheapTask(
+        make_scoped_ptr(new RasterWorkerPoolTaskImpl(
+                            picture_pile,
+                            task,
+                            reply)).PassAs<internal::WorkerPoolTask>());
+    return;
+  }
+
   Worker* worker = GetWorkerForNextTask();
 
   scoped_refptr<PicturePileImpl> picture_pile_clone =