cc: Simplify task and its derived classes.

cc/raster/gpu_tile_task_worker_pool.cc

 // Copyright 2014 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/gpu_tile_task_worker_pool.h"
 
 #include <stdint.h>
 
 #include <algorithm>
 
@@ skipping 148 matching lines @@
     bool must_support_alpha) const {
   return rasterizer_->resource_provider()->best_render_buffer_format();
 }
 
 bool GpuTileTaskWorkerPool::GetResourceRequiresSwizzle(
     bool must_support_alpha) const {
   // This doesn't require a swizzle because we rasterize to the correct format.
   return false;
 }
 
-void GpuTileTaskWorkerPool::CompleteTasks(const Task::Vector& tasks) {
+void GpuTileTaskWorkerPool::CompleteTasks(const DependencyTask::Vector& tasks) {
   for (auto& task : tasks) {
-    TileTask* tile_task = static_cast<TileTask*>(task.get());
-
-    tile_task->WillComplete();
-    tile_task->CompleteOnOriginThread(this);
-    tile_task->DidComplete();
+    task->WillComplete();
+    task->CompleteOnOriginThread(this);
+    task->DidComplete();
   }
   completed_tasks_.clear();
 }
 
 scoped_ptr<RasterBuffer> GpuTileTaskWorkerPool::AcquireBufferForRaster(
     const Resource* resource,
     uint64_t resource_content_id,
     uint64_t previous_content_id) {
   return scoped_ptr<RasterBuffer>(new RasterBufferImpl(
       rasterizer_.get(), resource, resource_content_id, previous_content_id));
 }
 
 void GpuTileTaskWorkerPool::ReleaseBufferForRaster(
     scoped_ptr<RasterBuffer> buffer) {
   // Nothing to do here. RasterBufferImpl destructor cleans up after itself.
 }
 
 }  // namespace cc