Standardize usage of virtual/override/final in extensions/

extensions/browser/api/storage/storage_frontend.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 EXTENSIONS_BROWSER_API_STORAGE_STORAGE_FRONTEND_H_
 #define EXTENSIONS_BROWSER_API_STORAGE_STORAGE_FRONTEND_H_
 
 #include <map>
 #include <string>
 
@@ skipping 16 matching lines @@
  public:
   // Returns the current instance for |context|.
   static StorageFrontend* Get(content::BrowserContext* context);
 
   // Creates with a specific |storage_factory|. Caller owns the object.
   static StorageFrontend* CreateForTesting(
       const scoped_refptr<SettingsStorageFactory>& storage_factory,
       content::BrowserContext* context);
 
   // Public so tests can create and delete their own instances.
-  virtual ~StorageFrontend();
+  ~StorageFrontend() override;
 
   // Returns the value store cache for |settings_namespace|.
   ValueStoreCache* GetValueStoreCache(
       settings_namespace::Namespace settings_namespace) const;
 
   // Returns true if |settings_namespace| is a valid namespace.
   bool IsStorageEnabled(settings_namespace::Namespace settings_namespace) const;
 
   // Runs |callback| with the storage area of the given |settings_namespace|
   // for the |extension|.
@@ skipping 42 matching lines @@
   // Maps a known namespace to its corresponding ValueStoreCache. The caches
   // are owned by this object.
   CacheMap caches_;
 
   DISALLOW_COPY_AND_ASSIGN(StorageFrontend);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_API_STORAGE_STORAGE_FRONTEND_H_