Update {virtual,override,final} to follow C++11 style in ash.

ash/system/tray/media_security/multi_profile_media_tray_item.h

Index: ash/system/tray/media_security/multi_profile_media_tray_item.h
diff --git a/ash/system/tray/media_security/multi_profile_media_tray_item.h b/ash/system/tray/media_security/multi_profile_media_tray_item.h
index f7b09f86dc83220f463ab6a694e8b4986583a5ab..fd9a729b1fb36fb9f514e68895ace1e8a7b6e4e0 100644
--- a/ash/system/tray/media_security/multi_profile_media_tray_item.h
+++ b/ash/system/tray/media_security/multi_profile_media_tray_item.h
@@ -18,11 +18,11 @@ class MultiProfileMediaTrayView;
 class ASH_EXPORT MultiProfileMediaTrayItem : public SystemTrayItem {
  public:
   explicit MultiProfileMediaTrayItem(SystemTray* system_tray);
-  virtual ~MultiProfileMediaTrayItem();
+  ~MultiProfileMediaTrayItem() override;
 
   // SystemTrayItem:
-  virtual views::View* CreateTrayView(user::LoginStatus status) override;
-  virtual void DestroyTrayView() override;
+  views::View* CreateTrayView(user::LoginStatus status) override;
+  void DestroyTrayView() override;
 
  private:
   tray::MultiProfileMediaTrayView* tray_view_;