Update editing classes to use OVERRIDE / FINAL when needed

Source/core/editing/markup.cpp

Index: Source/core/editing/markup.cpp
diff --git a/Source/core/editing/markup.cpp b/Source/core/editing/markup.cpp
index 30b8a47bb97ebb7aca484e012b0200519b6483bf..c447d141e01457b08d0a28e93c484bd2dd880143 100755
--- a/Source/core/editing/markup.cpp
+++ b/Source/core/editing/markup.cpp
@@ -130,7 +130,7 @@ private:
     String renderedText(const Node*, const Range*);
     String stringValueForRange(const Node*, const Range*);
     void appendElement(StringBuilder& out, Element*, bool addDisplayInline, RangeFullySelectsNode);
-    void appendElement(StringBuilder& out, Element* element, Namespaces*) OVERRIDE { appendElement(out, element, false, DoesFullySelectNode); }
+    virtual void appendElement(StringBuilder& out, Element* element, Namespaces*) OVERRIDE { appendElement(out, element, false, DoesFullySelectNode); }
 
     enum NodeTraversalMode { EmitString, DoNotEmitString };
     Node* traverseNodesForSerialization(Node* startNode, Node* pastEnd, NodeTraversalMode);