Add missing IWYU message_loop.h includes.

device/bluetooth/bluetooth_socket_thread.cc

 // Copyright 2014 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/bluetooth/bluetooth_socket_thread.h"
 
 #include "base/lazy_instance.h"
+#include "base/message_loop/message_loop.h"
 #include "base/sequenced_task_runner.h"
 #include "base/threading/thread.h"
 
 namespace device {
 
 base::LazyInstance<scoped_refptr<BluetoothSocketThread>>::DestructorAtExit
     g_instance = LAZY_INSTANCE_INITIALIZER;
 
 // static
 scoped_refptr<BluetoothSocketThread> BluetoothSocketThread::Get() {
@@ skipping 46 matching lines @@
 scoped_refptr<base::SequencedTaskRunner> BluetoothSocketThread::task_runner()
     const {
   DCHECK(active_socket_count_ > 0);
   DCHECK(thread_);
   DCHECK(task_runner_.get());
 
   return task_runner_;
 }
 
 }  // namespace device