Add missing IWYU message_loop.h includes.

components/browser_sync/test_profile_sync_service.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 "components/browser_sync/test_profile_sync_service.h"
 
 #include <utility>
 
+#include "base/message_loop/message_loop.h"
+
 namespace browser_sync {
 
 syncer::TestIdFactory* TestProfileSyncService::id_factory() {
   return &id_factory_;
 }
 
 syncer::WeakHandle<syncer::JsEventHandler>
 TestProfileSyncService::GetJsEventHandler() {
   return syncer::WeakHandle<syncer::JsEventHandler>();
 }
 
 TestProfileSyncService::TestProfileSyncService(
     ProfileSyncService::InitParams init_params)
     : ProfileSyncService(std::move(init_params)) {}
 
 TestProfileSyncService::~TestProfileSyncService() {}
 
 void TestProfileSyncService::OnConfigureDone(
     const syncer::DataTypeManager::ConfigureResult& result) {
   ProfileSyncService::OnConfigureDone(result);
   base::MessageLoop::current()->QuitWhenIdle();
 }
 
 syncer::UserShare* TestProfileSyncService::GetUserShare() const {
   return engine_->GetUserShare();
 }
 
 }  // namespace browser_sync