Fix virtual/override/final usage in Source/modules/.

Source/modules/webmidi/MIDIMessageEvent.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 41 matching lines @@
     }
 
     static PassRefPtrWillBeRawPtr<MIDIMessageEvent> create(const AtomicString& type, const MIDIMessageEventInit& initializer)
     {
         return adoptRefWillBeNoop(new MIDIMessageEvent(type, initializer));
     }
 
     double receivedTime() { return m_receivedTime; }
     PassRefPtr<DOMUint8Array> data() { return m_data; }
 
-    virtual const AtomicString& interfaceName() const override { return EventNames::MIDIMessageEvent; }
+    const AtomicString& interfaceName() const override { return EventNames::MIDIMessageEvent; }
 
     DEFINE_INLINE_VIRTUAL_TRACE() { Event::trace(visitor); }
 
 private:
     MIDIMessageEvent()
         : m_receivedTime(0) { }
 
     MIDIMessageEvent(double receivedTime, PassRefPtr<DOMUint8Array> data)
         : Event(EventTypeNames::midimessage, true, false)
         , m_receivedTime(receivedTime)
         , m_data(data) { }
 
     MIDIMessageEvent(const AtomicString& type, const MIDIMessageEventInit& initializer);
 
     double m_receivedTime;
     RefPtr<DOMUint8Array> m_data;
 };
 
 } // namespace blink
 
 #endif // MIDIMessageEvent_h