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

Source/core/xml/XPathVariableReference.h

 /*
  * Copyright 2005 Frerich Raabe <raabe@kde.org>
  *
  * 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
@@ skipping 20 matching lines @@
 namespace blink {
 
 namespace XPath {
 
 // Variable references are not used with XPathEvaluator.
 class VariableReference final : public Expression {
 public:
     explicit VariableReference(const String& name);
 
 private:
-    virtual Value evaluate(EvaluationContext&) const override;
-    virtual Value::Type resultType() const override { ASSERT_NOT_REACHED(); return Value::NumberValue; }
+    Value evaluate(EvaluationContext&) const override;
+    Value::Type resultType() const override { ASSERT_NOT_REACHED(); return Value::NumberValue; }
 
     String m_name;
 };
 
 }
 
 }
 #endif // XPathVariableReference_h