Standardize usage of virtual/override/final specifiers.

ui/views/controls/menu/menu_event_dispatcher_linux.h

Index: ui/views/controls/menu/menu_event_dispatcher_linux.h
diff --git a/ui/views/controls/menu/menu_event_dispatcher_linux.h b/ui/views/controls/menu/menu_event_dispatcher_linux.h
index a516d2e55e828e733b5abbadb9a29184ecd9469c..657cb7e300d734d09e2ff0637b6cd2497cf5fb29 100644
--- a/ui/views/controls/menu/menu_event_dispatcher_linux.h
+++ b/ui/views/controls/menu/menu_event_dispatcher_linux.h
@@ -16,12 +16,12 @@ namespace internal {
 class MenuEventDispatcher : public ui::PlatformEventDispatcher {
  public:
   explicit MenuEventDispatcher(MenuController* menu_controller);
-  virtual ~MenuEventDispatcher();
+  ~MenuEventDispatcher() override;
 
  private:
   // ui::PlatformEventDispatcher:
-  virtual bool CanDispatchEvent(const ui::PlatformEvent& event) override;
-  virtual uint32_t DispatchEvent(const ui::PlatformEvent& event) override;
+  bool CanDispatchEvent(const ui::PlatformEvent& event) override;
+  uint32_t DispatchEvent(const ui::PlatformEvent& event) override;
 
   MenuController* menu_controller_;