Provide default implementations for NotificationDelegate methods.

chrome/browser/chromeos/power/peripheral_battery_observer.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 "chrome/browser/chromeos/power/peripheral_battery_observer.h"
 
 #include <vector>
 
 #include "ash/shell.h"
 #include "ash/strings/grit/ash_strings.h"
@@ skipping 56 matching lines @@
   std::string address = JoinString(result, ':');
   return address;
 }
 
 class PeripheralBatteryNotificationDelegate : public NotificationDelegate {
  public:
   explicit PeripheralBatteryNotificationDelegate(const std::string& id)
       : id_(id) {}
 
   // Overridden from NotificationDelegate:
-  virtual void Display() override {}
-  virtual void Error() override {}
-  virtual void Close(bool by_user) override {}
-  virtual void Click() override {}
   virtual std::string id() const override { return id_; }
 
  private:
   virtual ~PeripheralBatteryNotificationDelegate() {}
 
   const std::string id_;
 
   DISALLOW_COPY_AND_ASSIGN(PeripheralBatteryNotificationDelegate);
 };
 
@@ skipping 144 matching lines @@
 
 void PeripheralBatteryObserver::CancelNotification(const std::string& address) {
   // If last_used_profile_ is NULL then no notification has been posted yet.
   if (notification_profile_) {
     g_browser_process->notification_ui_manager()->CancelById(
         address, NotificationUIManager::GetProfileID(notification_profile_));
   }
 }
 
 }  // namespace chromeos