Add missing IWYU message_loop.h includes.

device/gamepad/gamepad_provider.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 "device/gamepad/gamepad_provider.h"
 
 #include <stddef.h>
 #include <string.h>
 #include <cmath>
 #include <utility>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
+#include "base/message_loop/message_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/third_party/dynamic_annotations/dynamic_annotations.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
 #include "device/gamepad/gamepad_data_fetcher.h"
 #include "device/gamepad/gamepad_data_fetcher_manager.h"
 #include "device/gamepad/gamepad_user_gesture.h"
 #include "mojo/public/cpp/system/platform_handle.h"
@@ skipping 294 matching lines @@
     ever_had_user_gesture_ = true;
     for (size_t i = 0; i < user_gesture_observers_.size(); i++) {
       user_gesture_observers_[i].task_runner->PostTask(
           FROM_HERE, user_gesture_observers_[i].closure);
     }
     user_gesture_observers_.clear();
   }
 }
 
 }  // namespace device