Automated IWYU fix for TaskRunner includes.

cc/trees/layer_tree_host_impl.h

 // Copyright 2011 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.
 
 #ifndef CC_TREES_LAYER_TREE_HOST_IMPL_H_
 #define CC_TREES_LAYER_TREE_HOST_IMPL_H_
 
 #include <stddef.h>
 
 #include <bitset>
 #include <memory>
 #include <set>
 #include <string>
 #include <unordered_map>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/macros.h"
+#include "base/sequenced_task_runner.h"
 #include "base/time/time.h"
 #include "cc/base/synced_property.h"
 #include "cc/benchmarks/micro_benchmark_controller_impl.h"
 #include "cc/cc_export.h"
 #include "cc/input/browser_controls_offset_manager_client.h"
 #include "cc/input/input_handler.h"
 #include "cc/input/scrollbar_animation_controller.h"
 #include "cc/layers/layer_collections.h"
 #include "cc/output/begin_frame_args.h"
 #include "cc/output/compositor_frame_sink_client.h"
@@ skipping 848 matching lines @@
   bool touchpad_and_wheel_scroll_latching_enabled_;
 
   ImplThreadPhase impl_thread_phase_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_IMPL_H_