Initial implementation of new-style notification

ui/message_center/message_center_switches.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 "ui/message_center/message_center_switches.h"
 
 namespace switches {
 
 // Enables message center to always move other notifications upwards when a
 // notification is removed, no matter whether the message center is displayed
 // top down or not.
 const char kEnableMessageCenterAlwaysScrollUpUponNotificationRemoval[] =
     "enable-message-center-always-scroll-up-upon-notification-removal";
 
 // Flag to enable or disable notification changes while the message center
 // opens. This flag will be removed once the feature gets stable.
 const char kMessageCenterChangesWhileOpen[] =
     "message-center-changes-while-open";
 
+// Flag to enable or disable new-style notification. This flag will be removed
+// once the feature gets stable.
+const char kEnableMessageCenterNewStyleNotification[] =
+    "enabled-new-style-notification";
+const char kDisableMessageCenterNewStyleNotification[] =
+    "disabled-new-style-notification";
+
 }  // namespace switches