Remove the OnError method from notification delegates.

ui/message_center/notification.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_NOTIFICATION_H_
 #define UI_MESSAGE_CENTER_NOTIFICATION_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 167 matching lines @@
   const RichNotificationData& rich_notification_data() const {
     return optional_fields_;
   }
 
   // Set the priority to SYSTEM. The system priority user needs to call this
   // method explicitly, to avoid setting it accidentally.
   void SetSystemPriority();
 
   // Delegate actions.
   void Display() const { delegate()->Display(); }
-  void Error() const { delegate()->Error(); }
   bool HasClickedListener() const { return delegate()->HasClickedListener(); }
   void Click() const { delegate()->Click(); }
   void ButtonClick(int index) const { delegate()->ButtonClick(index); }
   void Close(bool by_user) const { delegate()->Close(by_user); }
 
   // Helper method to create a simple system notification. |click_callback|
   // will be invoked when the notification is clicked.
   static scoped_ptr<Notification> CreateSystemNotification(
       const std::string& notification_id,
       const base::string16& title,
@@ skipping 27 matching lines @@
   bool is_read_;  // True if this has been seen in the message center.
 
   // A proxy object that allows access back to the JavaScript object that
   // represents the notification, for firing events.
   scoped_refptr<NotificationDelegate> delegate_;
 };
 
 }  // namespace message_center
 
 #endif  // UI_MESSAGE_CENTER_NOTIFICATION_H_