Update XML classes to use OVERRIDE / FINAL when needed

Source/core/xml/XPathStep.h

 /*
  * Copyright (C) 2005 Frerich Raabe <raabe@kde.org>
  * Copyright (C) 2006, 2009 Apple Inc.
  *
  * 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.
@@ skipping 20 matching lines @@
 #include "core/xml/XPathNodeSet.h"
 
 namespace WebCore {
 
 class Node;
 
 namespace XPath {
 
 class Predicate;
 
-class Step : public ParseNode {
+class Step FINAL : public ParseNode {
     WTF_MAKE_NONCOPYABLE(Step);
     WTF_MAKE_FAST_ALLOCATED;
 public:
     enum Axis {
         AncestorAxis, AncestorOrSelfAxis, AttributeAxis,
         ChildAxis, DescendantAxis, DescendantOrSelfAxis,
         FollowingAxis, FollowingSiblingAxis, NamespaceAxis,
         ParentAxis, PrecedingAxis, PrecedingSiblingAxis,
         SelfAxis
     };
@@ skipping 35 matching lines @@
         Kind m_kind;
         AtomicString m_data;
         AtomicString m_namespaceURI;
 
         // When possible, we merge some or all predicates with node test for better performance.
         Vector<OwnPtr<Predicate> > m_mergedPredicates;
     };
 
     Step(Axis, const NodeTest&);
     Step(Axis, const NodeTest&, Vector<OwnPtr<Predicate> >&);
-    ~Step();
+    virtual ~Step();
 
     void optimize();
 
     void evaluate(Node* context, NodeSet&) const;
 
     Axis axis() const { return m_axis; }
     const NodeTest& nodeTest() const { return m_nodeTest; }
 
 private:
     friend void optimizeStepPair(Step*, Step*, bool&);
     bool predicatesAreContextListInsensitive() const;
 
     void parseNodeTest(const String&);
     void nodesInAxis(Node* context, NodeSet&) const;
     String namespaceFromNodetest(const String& nodeTest) const;
 
     Axis m_axis;
     NodeTest m_nodeTest;
     Vector<OwnPtr<Predicate> > m_predicates;
 };
 
 void optimizeStepPair(Step*, Step*, bool& dropSecondStep);
 
 } // namespace XPath
 
 } // namespace WebCore
 
 #endif // XPathStep_h