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

Source/core/xml/XPathVariableReference.h

Index: Source/core/xml/XPathVariableReference.h
diff --git a/Source/core/xml/XPathVariableReference.h b/Source/core/xml/XPathVariableReference.h
index bae90cc0bc29ee0c4c33ac51abd7ef1baa0f4432..917826835e6bb4d96a87d45ad6d7f89a529da839 100644
--- a/Source/core/xml/XPathVariableReference.h
+++ b/Source/core/xml/XPathVariableReference.h
@@ -38,8 +38,8 @@ 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;
 };