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

Source/core/dom/StaticNodeList.h

Index: Source/core/dom/StaticNodeList.h
diff --git a/Source/core/dom/StaticNodeList.h b/Source/core/dom/StaticNodeList.h
index ad5e7d412f18c3b1b2228cc46cd32188512cc6dc..a1bebef8ce823ce2461f7379320c41b7e52614a6 100644
--- a/Source/core/dom/StaticNodeList.h
+++ b/Source/core/dom/StaticNodeList.h
@@ -50,10 +50,10 @@ public:
         return adoptRefWillBeNoop(new StaticNodeTypeList);
     }
 
-    virtual ~StaticNodeTypeList();
+    ~StaticNodeTypeList() override;
 
-    virtual unsigned length() const override;
-    virtual NodeType* item(unsigned index) const override;
+    unsigned length() const override;
+    NodeType* item(unsigned index) const override;
 
     DECLARE_VIRTUAL_TRACE();