Update remaining HTML classes to use OVERRIDE / FINAL when needed

Source/core/html/track/TrackEvent.h

Index: Source/core/html/track/TrackEvent.h
diff --git a/Source/core/html/track/TrackEvent.h b/Source/core/html/track/TrackEvent.h
index 606bc1488cca3ea25798d6f308fee5f384e88d71..17fbf09b6c4ac1f5a6ad56cd4f9f31191555f619 100644
--- a/Source/core/html/track/TrackEvent.h
+++ b/Source/core/html/track/TrackEvent.h
@@ -37,7 +37,7 @@ struct TrackEventInit : public EventInit {
     RefPtr<TrackBase> track;
 };
 
-class TrackEvent : public Event {
+class TrackEvent FINAL : public Event {
 public:
     virtual ~TrackEvent();
 
@@ -51,7 +51,7 @@ public:
         return adoptRef(new TrackEvent(type, initializer));
     }
 
-    virtual const AtomicString& interfaceName() const;
+    virtual const AtomicString& interfaceName() const OVERRIDE;
 
     TrackBase* track() const { return m_track.get(); }