Add preliminary support for hw-accelerated tile rasterization.

cc/resources/worker_pool.h

Index: cc/resources/worker_pool.h
diff --git a/cc/resources/worker_pool.h b/cc/resources/worker_pool.h
index cc8c39f3642a0997bc990ba9484aab87612909df..b4d2623842d0a70482ff56373b39be9785249ddf 100644
--- a/cc/resources/worker_pool.h
+++ b/cc/resources/worker_pool.h
@@ -105,9 +105,6 @@ class CC_EXPORT WorkerPool {
   // completed.
   virtual void Shutdown();
 
-  // Force a check for completed tasks.
-  virtual void CheckForCompletedTasks();
-
  protected:
   // A task graph contains a unique set of tasks with edges between
   // dependencies pointing in the direction of the dependents. Each task
@@ -124,6 +121,9 @@ class CC_EXPORT WorkerPool {
   // but completion of them is still processed.
   void SetTaskGraph(TaskGraph* graph);
 
+  // Force a check for completed tasks.
+  void CheckForCompletedWorkerTasks();
+
  private:
   class Inner;
   friend class Inner;