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

ash/system/tray/media_security/multi_profile_media_tray_item.cc

Index: ash/system/tray/media_security/multi_profile_media_tray_item.cc
diff --git a/ash/system/tray/media_security/multi_profile_media_tray_item.cc b/ash/system/tray/media_security/multi_profile_media_tray_item.cc
index a6abc2e0a2e17cf37e28b75b99a577fc8ff2ffc8..870d4cd46fd8a81a252afdbf6445ebdc841fcbac 100644
--- a/ash/system/tray/media_security/multi_profile_media_tray_item.cc
+++ b/ash/system/tray/media_security/multi_profile_media_tray_item.cc
@@ -35,13 +35,13 @@ class MultiProfileMediaTrayView : public TrayItemView,
     set_id(VIEW_ID_MEDIA_TRAY_VIEW);
   }
 
-  virtual ~MultiProfileMediaTrayView() {
+  ~MultiProfileMediaTrayView() override {
     Shell::GetInstance()->system_tray_notifier()->RemoveMediaCaptureObserver(
         this);
   }
 
   // MediaCaptureObserver:
-  virtual void OnMediaCaptureChanged() override {
+  void OnMediaCaptureChanged() override {
     MediaDelegate* media_delegate = Shell::GetInstance()->media_delegate();
     SessionStateDelegate* session_state_delegate =
         Shell::GetInstance()->session_state_delegate();