Do not allow creating dummy notifier id from production, for safety.

ui/message_center/message_center.h

 // 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.
 
 #ifndef UI_MESSAGE_CENTER_MESSAGE_CENTER_H_
 #define UI_MESSAGE_CENTER_MESSAGE_CENTER_H_
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/message_center/message_center_export.h"
 #include "ui/message_center/message_center_types.h"
 #include "ui/message_center/notification_list.h"
 #include "ui/message_center/notification_types.h"
 
-class TrayViewControllerTest;
-
 namespace base {
 class DictionaryValue;
 }
 
 // Interface to manage the NotificationList. The client (e.g. Chrome) calls
 // [Add|Remove|Update]Notification to create and update notifications in the
 // list. It also sends those changes to its observers when a notification
 // is shown, closed, or clicked on.
 
 namespace message_center {
@@ skipping 130 matching lines @@
 
   // UI classes should call this when there is cause to leave popups visible for
   // longer than the default (for example, when the mouse hovers over a popup).
   virtual void PausePopupTimers() = 0;
 
   // UI classes should call this when the popup timers should restart (for
   // example, after the mouse leaves the popup.)
   virtual void RestartPopupTimers() = 0;
 
  protected:
-  friend class ::TrayViewControllerTest;
+  friend class TrayViewControllerTest;
   friend class test::MessagePopupCollectionTest;
   virtual void DisableTimersForTest() = 0;
 
   MessageCenter();
   virtual ~MessageCenter();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MessageCenter);
 };
 
 }  // namespace message_center
 
 #endif  // UI_MESSAGE_CENTER_MESSAGE_CENTER_H_