Standardize usage of virtual/override/final in chrome/browser/password_manager

chrome/browser/password_manager/null_password_store_service.h

 // Copyright 2014 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_PASSWORD_MANAGER_NULL_PASSWORD_STORE_SERVICE_H_
 #define CHROME_BROWSER_PASSWORD_MANAGER_NULL_PASSWORD_STORE_SERVICE_H_
 
 #include "chrome/browser/password_manager/password_store_factory.h"
 
 class PasswordStore;
 
 namespace content {
 class BrowserContext;
 }
 
 class NullPasswordStoreService : public PasswordStoreService {
  public:
   static KeyedService* Build(content::BrowserContext* profile);
 
  private:
   NullPasswordStoreService();
 
-  virtual ~NullPasswordStoreService();
+  ~NullPasswordStoreService() override;
 
   DISALLOW_COPY_AND_ASSIGN(NullPasswordStoreService);
 };
 
 #endif  // CHROME_BROWSER_PASSWORD_MANAGER_NULL_PASSWORD_STORE_SERVICE_H_