Automated IWYU fix for TaskRunner includes.

chrome/browser/chromeos/arc/extensions/arc_support_message_host.cc

 // 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 "chrome/browser/chromeos/arc/extensions/arc_support_message_host.h"
 
 #include <string>
 
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
+#include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "chrome/browser/chromeos/arc/arc_session_manager.h"
 #include "chrome/browser/chromeos/arc/arc_support_host.h"
 
 namespace arc {
 
 // static
 const char ArcSupportMessageHost::kHostName[] = "com.google.arc_support";
 
 // static
@@ skipping 60 matching lines @@
 
   observer_->OnMessage(*message);
 }
 
 scoped_refptr<base::SingleThreadTaskRunner> ArcSupportMessageHost::task_runner()
     const {
   return base::ThreadTaskRunnerHandle::Get();
 }
 
 }  // namespace arc