Add missing IWYU message_loop.h includes.

chrome/browser/extensions/permissions_updater_unittest.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/browser/extensions/permissions_updater.h"
 
 #include <utility>
 
 #include "base/files/file_path.h"
 #include "base/json/json_file_value_serializer.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted.h"
+#include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/values.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_service_test_base.h"
 #include "chrome/browser/extensions/extension_util.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/extensions/extension_test_util.h"
 #include "chrome/test/base/testing_profile.h"
 #include "components/crx_file/id_util.h"
@@ skipping 490 matching lines @@
   EXPECT_TRUE(extension->permissions_data()->HasAPIPermission(
       APIPermission::kManagement));
   EXPECT_FALSE(extension->permissions_data()->HasAPIPermission(
       APIPermission::kCookie));
 
   // Unset the delegate.
   PermissionsUpdater::SetPlatformDelegate(nullptr);
 }
 
 }  // namespace extensions