cc: Simplify Task and its derived classes.

cc/raster/task.cc

Index: cc/raster/task.cc
diff --git a/cc/raster/task_graph_runner.cc b/cc/raster/task.cc
similarity index 73%
rename from cc/raster/task_graph_runner.cc
rename to cc/raster/task.cc
index 4f1af43ad43901309131886aa2dd6d5c6de1343a..c19e549462830731ab05d09d536025d86861a7c5 100644
--- a/cc/raster/task_graph_runner.cc
+++ b/cc/raster/task.cc
@@ -1,15 +1,10 @@
-// Copyright 2014 The Chromium Authors. All rights reserved.
+// Copyright 2016 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/task_graph_runner.h"
+#include "cc/raster/task.h"
 
-#include <algorithm>
-#include <utility>
-
-#include "base/atomic_sequence_num.h"
-#include "base/threading/thread_restrictions.h"
-#include "base/trace_event/trace_event.h"
+#include "base/logging.h"
 
 namespace cc {