Fix virtual/override/final usage in Source/core/editing/.

Source/core/editing/MergeIdenticalElementsCommand.h

 /*
  * Copyright (C) 2005, 2006, 2008 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 24 matching lines @@
     static PassRefPtrWillBeRawPtr<MergeIdenticalElementsCommand> create(PassRefPtrWillBeRawPtr<Element> element1, PassRefPtrWillBeRawPtr<Element> element2)
     {
         return adoptRefWillBeNoop(new MergeIdenticalElementsCommand(element1, element2));
     }
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     MergeIdenticalElementsCommand(PassRefPtrWillBeRawPtr<Element>, PassRefPtrWillBeRawPtr<Element>);
 
-    virtual void doApply() override;
-    virtual void doUnapply() override;
+    void doApply() override;
+    void doUnapply() override;
 
     RefPtrWillBeMember<Element> m_element1;
     RefPtrWillBeMember<Element> m_element2;
     RefPtrWillBeMember<Node> m_atChild;
 };
 
 } // namespace blink
 
 #endif // MergeIdenticalElementsCommand_h