Clean up virtual methods in MarkupAccumulator and subclasses

Source/core/page/PageSerializer.cpp

Index: Source/core/page/PageSerializer.cpp
diff --git a/Source/core/page/PageSerializer.cpp b/Source/core/page/PageSerializer.cpp
index 033f8c592242092ab4025a892c7296d51e664b8c..cbcf0d2a645705b641d623ee60f3e1e21c7b9609 100644
--- a/Source/core/page/PageSerializer.cpp
+++ b/Source/core/page/PageSerializer.cpp
@@ -99,16 +99,16 @@ static const QualifiedName& frameOwnerURLAttributeName(const HTMLFrameOwnerEleme
     return frameOwner.hasTagName(HTMLNames::objectTag) ? HTMLNames::dataAttr : HTMLNames::srcAttr;
 }
 
-class SerializerMarkupAccumulator : public WebCore::MarkupAccumulator {
+class SerializerMarkupAccumulator FINAL : public MarkupAccumulator {
 public:
     SerializerMarkupAccumulator(PageSerializer*, Document*, Vector<Node*>*);
     virtual ~SerializerMarkupAccumulator();
 
 protected:
-    virtual void appendText(StringBuilder& out, Text*);
-    virtual void appendElement(StringBuilder& out, Element*, Namespaces*);
-    virtual void appendCustomAttributes(StringBuilder& out, Element*, Namespaces*);
-    virtual void appendEndTag(Node*);
+    virtual void appendText(StringBuilder& out, Text*) OVERRIDE;
+    virtual void appendElement(StringBuilder& out, Element*, Namespaces*) OVERRIDE;
+    virtual void appendCustomAttributes(StringBuilder& out, Element*, Namespaces*) OVERRIDE;
+    virtual void appendEndTag(Node*) OVERRIDE;
 
 private:
     PageSerializer* m_serializer;