Remove the OnError method from notification delegates.

chrome/browser/notifications/message_center_notifications_browsertest.cc

 // 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.
 
 #include <map>
 #include <string>
 
 #include "base/command_line.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 55 matching lines @@
     return g_browser_process->message_center();
   }
 
   Profile* profile() { return browser()->profile(); }
 
   class TestDelegate : public NotificationDelegate {
    public:
     explicit TestDelegate(const std::string& id) : id_(id) {}
 
     void Display() override { log_ += "Display_"; }
-    void Error() override { log_ += "Error_"; }
     void Close(bool by_user) override {
       log_ += "Close_";
       log_ += ( by_user ? "by_user_" : "programmatically_");
     }
     void Click() override { log_ += "Click_"; }
     void ButtonClick(int button_index) override {
       log_ += "ButtonClick_";
       log_ += base::IntToString(button_index) + "_";
     }
     std::string id() const override { return id_; }
@@ skipping 264 matching lines @@
   manager()->Update(notification, profile());
 
   // Expect that the progress notification update is performed.
   EXPECT_EQ(base::StringPrintf("update-%s", notification_id.c_str()),
             observer.log(notification_id));
 
   delegate->Release();
 }
 
 #endif  // !defined(OS_MACOSX)