Remove the OnError method from notification delegates.

chrome/browser/notifications/notification_test_util.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 CHROME_BROWSER_NOTIFICATIONS_NOTIFICATION_TEST_UTIL_H_
 #define CHROME_BROWSER_NOTIFICATIONS_NOTIFICATION_TEST_UTIL_H_
 
 #include <set>
 #include <string>
 
@@ skipping 29 matching lines @@
 // static void log(string);
 template<class Logger>
 class LoggingNotificationDelegate : public NotificationDelegate {
  public:
   explicit LoggingNotificationDelegate(std::string id) : notification_id_(id) {}
 
   // NotificationObjectProxy override
   virtual void Display() override {
     Logger::log("notification displayed\n");
   }
-  virtual void Error() override {
-    Logger::log("notification error\n");
-  }
   virtual void Click() override {
     Logger::log("notification clicked\n");
   }
   virtual void ButtonClick(int index) override {
     Logger::log("notification button clicked\n");
   }
   virtual void Close(bool by_user) override {
     if (by_user)
       Logger::log("notification closed by user\n");
     else
@@ skipping 58 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(StubNotificationUIManager);
   Notification notification_;
   Profile* profile_;
   std::string dismissed_id_;
   GURL welcome_origin_;
   bool welcomed_;
   size_t added_notifications_;
 };
 
 #endif  // CHROME_BROWSER_NOTIFICATIONS_NOTIFICATION_TEST_UTIL_H_