Fix virtual/override/final usage in the rest of Source/core/.

Source/core/events/PageTransitionEvent.h

 /*
  * Copyright (C) 2009 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 29 matching lines @@
     }
     static PassRefPtrWillBeRawPtr<PageTransitionEvent> create(const AtomicString& type, bool persisted)
     {
         return adoptRefWillBeNoop(new PageTransitionEvent(type, persisted));
     }
     static PassRefPtrWillBeRawPtr<PageTransitionEvent> create(const AtomicString& type, const PageTransitionEventInit& initializer)
     {
         return adoptRefWillBeNoop(new PageTransitionEvent(type, initializer));
     }
 
-    virtual ~PageTransitionEvent();
+    ~PageTransitionEvent() override;
 
-    virtual const AtomicString& interfaceName() const override;
+    const AtomicString& interfaceName() const override;
 
     bool persisted() const { return m_persisted; }
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     PageTransitionEvent();
     PageTransitionEvent(const AtomicString& type, bool persisted);
     PageTransitionEvent(const AtomicString&, const PageTransitionEventInit&);
 
     bool m_persisted;
 };
 
 } // namespace blink
 
 #endif // PageTransitionEvent_h