Standardize usage of virtual/override/final in extensions/

extensions/browser/api/storage/storage_frontend.cc

 // 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.
 
 #include "extensions/browser/api/storage/storage_frontend.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/files/file_path.h"
 #include "base/json/json_reader.h"
@@ skipping 18 matching lines @@
     LAZY_INSTANCE_INITIALIZER;
 
 // Settings change Observer which forwards changes on to the extension
 // processes for |context| and its incognito partner if it exists.
 class DefaultObserver : public SettingsObserver {
  public:
   explicit DefaultObserver(BrowserContext* context)
       : browser_context_(context) {}
 
   // SettingsObserver implementation.
-  virtual void OnSettingsChanged(
-      const std::string& extension_id,
-      settings_namespace::Namespace settings_namespace,
-      const std::string& change_json) override {
+  void OnSettingsChanged(const std::string& extension_id,
+                         settings_namespace::Namespace settings_namespace,
+                         const std::string& change_json) override {
     // TODO(gdk): This is a temporary hack while the refactoring for
     // string-based event payloads is removed. http://crbug.com/136045
     scoped_ptr<base::ListValue> args(new base::ListValue());
     args->Append(base::JSONReader::Read(change_json));
     args->Append(new base::StringValue(settings_namespace::ToString(
         settings_namespace)));
     scoped_ptr<Event> event(new Event(
         core_api::storage::OnChanged::kEventName, args.Pass()));
     EventRouter::Get(browser_context_)
         ->DispatchEventToExtension(extension_id, event.Pass());
@@ skipping 119 matching lines @@
 // static
 BrowserContextKeyedAPIFactory<StorageFrontend>*
 StorageFrontend::GetFactoryInstance() {
   return g_factory.Pointer();
 }
 
 // static
 const char* StorageFrontend::service_name() { return "StorageFrontend"; }
 
 }  // namespace extensions