Specialize InsertionPoint attach/detach.

sky/engine/core/dom/Element.h

Index: sky/engine/core/dom/Element.h
diff --git a/sky/engine/core/dom/Element.h b/sky/engine/core/dom/Element.h
index 4f5a234c1a13f153fd368509f777d5e275f99138..2771a576bae818ad4cd323c86ac2ef5fd8c01b07 100644
--- a/sky/engine/core/dom/Element.h
+++ b/sky/engine/core/dom/Element.h
@@ -196,8 +196,9 @@ public:
 
     bool hasEquivalentAttributes(const Element* other) const;
 
-    virtual void attach(const AttachContext& = AttachContext()) override;
-    virtual void detach(const AttachContext& = AttachContext()) override;
+    void attach(const AttachContext& = AttachContext()) final;
+    void detach(const AttachContext& = AttachContext()) final;
+
     virtual RenderObject* createRenderer(RenderStyle*);
     void recalcStyle(StyleRecalcChange, Text* nextTextSibling = 0);
     void setAnimationStyleChange(bool);