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

Source/core/svg/SVGPathSegCurvetoQuadraticSmoothRel.h

 /*
  * Copyright (C) 2004, 2005, 2006 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2008 Rob Buis <buis@kde.org>
  * Copyright (C) 2013 Samsung Electronics. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 25 matching lines @@
 
     PassRefPtrWillBeRawPtr<SVGPathSeg> clone() override
     {
         return adoptRefWillBeNoop(new SVGPathSegCurvetoQuadraticSmoothRel(nullptr, x(), y()));
     }
 
 private:
     SVGPathSegCurvetoQuadraticSmoothRel(SVGPathElement* element, float x, float y)
         : SVGPathSegSingleCoordinate(element, x, y) { }
 
-    virtual unsigned short pathSegType() const override { return PATHSEG_CURVETO_QUADRATIC_SMOOTH_REL; }
-    virtual String pathSegTypeAsLetter() const override { return "t"; }
+    unsigned short pathSegType() const override { return PATHSEG_CURVETO_QUADRATIC_SMOOTH_REL; }
+    String pathSegTypeAsLetter() const override { return "t"; }
 };
 
 } // namespace blink
 
 #endif // SVGPathSegCurvetoQuadraticSmoothRel_h