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

chrome/browser/browsing_data/mock_browsing_data_service_worker_helper.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_BROWSING_DATA_MOCK_BROWSING_DATA_SERVICE_WORKER_HELPER_H_
 #define CHROME_BROWSER_BROWSING_DATA_MOCK_BROWSING_DATA_SERVICE_WORKER_HELPER_H_
 
 #include <list>
 #include <map>
 
@@ skipping 18 matching lines @@
   void Notify();
 
   // Marks all service worker files as existing.
   void Reset();
 
   // Returns true if all service worker files were deleted since the last
   // Reset() invokation.
   bool AllDeleted();
 
   // BrowsingDataServiceWorkerHelper.
-  virtual void StartFetching(const base::Callback<void(
+  void StartFetching(const base::Callback<void(
       const std::list<content::ServiceWorkerUsageInfo>&)>& callback) override;
-  virtual void DeleteServiceWorkers(const GURL& origin) override;
+  void DeleteServiceWorkers(const GURL& origin) override;
 
  private:
-  virtual ~MockBrowsingDataServiceWorkerHelper();
+  ~MockBrowsingDataServiceWorkerHelper() override;
 
   base::Callback<void(const std::list<content::ServiceWorkerUsageInfo>&)>
       callback_;
   std::map<GURL, bool> origins_;
   std::list<content::ServiceWorkerUsageInfo> response_;
 
   DISALLOW_COPY_AND_ASSIGN(MockBrowsingDataServiceWorkerHelper);
 };
 
 #endif  // CHROME_BROWSER_BROWSING_DATA_MOCK_BROWSING_DATA_SERVICE_WORKER_HELPER_H_