Standardize usage of virtual/override/final in ui/

ui/app_list/app_list_model.h

Index: ui/app_list/app_list_model.h
diff --git a/ui/app_list/app_list_model.h b/ui/app_list/app_list_model.h
index 81c9854fb17ad1083fa4410a055e8757e3343877..fb18d854710264740b0437b9becdc43f964ff71d 100644
--- a/ui/app_list/app_list_model.h
+++ b/ui/app_list/app_list_model.h
@@ -42,7 +42,7 @@ class APP_LIST_EXPORT AppListModel : public AppListItemListObserver {
   typedef ui::ListModel<SearchResult> SearchResults;
 
   AppListModel();
-  virtual ~AppListModel();
+  ~AppListModel() override;
 
   void AddObserver(AppListModelObserver* observer);
   void RemoveObserver(AppListModelObserver* observer);
@@ -133,9 +133,9 @@ class APP_LIST_EXPORT AppListModel : public AppListItemListObserver {
 
  private:
   // AppListItemListObserver
-  virtual void OnListItemMoved(size_t from_index,
-                               size_t to_index,
-                               AppListItem* item) override;
+  void OnListItemMoved(size_t from_index,
+                       size_t to_index,
+                       AppListItem* item) override;
 
   // Returns an existing folder matching |folder_id| or creates a new folder.
   AppListFolderItem* FindOrCreateFolderItem(const std::string& folder_id);