Add missing IWYU message_loop.h includes.

chrome/service/service_process.cc

 // Copyright (c) 2012 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/service/service_process.h"
 
 #include <algorithm>
 #include <utility>
 #include <vector>
 
 #include "base/base_switches.h"
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/environment.h"
 #include "base/i18n/rtl.h"
 #include "base/location.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/singleton.h"
+#include "base/message_loop/message_loop.h"
 #include "base/path_service.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string16.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/task_scheduler/scheduler_worker_pool_params.h"
 #include "base/task_scheduler/task_scheduler.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
@@ skipping 419 matching lines @@
     } else {
       Shutdown();
     }
   }
 }
 
 ServiceProcess::~ServiceProcess() {
   Teardown();
   g_service_process = NULL;
 }