Add missing IWYU message_loop.h includes.

chrome/browser/devtools/device/adb/mock_adb_server.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 "chrome/browser/devtools/device/adb/mock_adb_server.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/location.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/weak_ptr.h"
+#include "base/message_loop/message_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/test/browser_test.h"
 #include "content/public/test/test_utils.h"
@@ skipping 591 matching lines @@
   content::RunMessageLoop();
 }
 
 void StopMockAdbServer() {
   BrowserThread::PostTaskAndReply(BrowserThread::IO, FROM_HERE,
                                   base::BindOnce(&StopMockAdbServerOnIOThread),
                                   base::MessageLoop::QuitWhenIdleClosure());
   content::RunMessageLoop();
 }