Standardize usage of virtual/override/final specifiers.

ash/shelf/app_list_shelf_item_delegate.h

Index: ash/shelf/app_list_shelf_item_delegate.h
diff --git a/ash/shelf/app_list_shelf_item_delegate.h b/ash/shelf/app_list_shelf_item_delegate.h
index f40d2c620012f8c18eb9dfce47ed38acd549331b..5d04faca5662cd7d59775b1317a00da355a5ccfb 100644
--- a/ash/shelf/app_list_shelf_item_delegate.h
+++ b/ash/shelf/app_list_shelf_item_delegate.h
@@ -16,16 +16,16 @@ class AppListShelfItemDelegate : public ShelfItemDelegate {
  public:
   AppListShelfItemDelegate();
 
-  virtual ~AppListShelfItemDelegate();
+  ~AppListShelfItemDelegate() override;
 
   // ShelfItemDelegate:
-  virtual bool ItemSelected(const ui::Event& event) override;
-  virtual base::string16 GetTitle() override;
-  virtual ui::MenuModel* CreateContextMenu(aura::Window* root_window) override;
-  virtual ShelfMenuModel* CreateApplicationMenu(int event_flags) override;
-  virtual bool IsDraggable() override;
-  virtual bool ShouldShowTooltip() override;
-  virtual void Close() override;
+  bool ItemSelected(const ui::Event& event) override;
+  base::string16 GetTitle() override;
+  ui::MenuModel* CreateContextMenu(aura::Window* root_window) override;
+  ShelfMenuModel* CreateApplicationMenu(int event_flags) override;
+  bool IsDraggable() override;
+  bool ShouldShowTooltip() override;
+  void Close() override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AppListShelfItemDelegate);