Adds a first-run balloon to the Windows notification center.

ui/message_center/message_center_tray_delegate.h

 // Copyright (c) 2013 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_TRAY_DELEGATE_H_
 #define UI_MESSAGE_CENTER_MESSAGE_CENTER_TRAY_DELEGATE_H_
 
 #include "ui/message_center/message_center_export.h"
 
 namespace message_center {
@@ skipping 20 matching lines @@
 
   // Display the message center containing all undismissed notifications to the
   // user.  Returns true if the center was actually displayed to the user.
   virtual bool ShowMessageCenter() = 0;
 
   // Remove the message center from the UI.
   virtual void HideMessageCenter() = 0;
 
   // Display the notifier settings as a bubble.
   virtual bool ShowNotifierSettings() = 0;
+
+  // Show a platform-specific UI that informs the user how to open the message
+  // center.
+  virtual void DisplayFirstRunBalloon() {};
 };
 
 }  // namespace message_center
 
 #endif  // UI_MESSAGE_CENTER_MESSAGE_CENTER_TRAY_DELEGATE_H_