Hide isXXX() type checking methods in subclasses

Source/core/dom/Element.h

Index: Source/core/dom/Element.h
diff --git a/Source/core/dom/Element.h b/Source/core/dom/Element.h
index 37a662c17dc8b064c4f144671cc5528ee507c081..8395c8fc608cc04d4ef3e22a81b9ebce2dc5b8e2 100644
--- a/Source/core/dom/Element.h
+++ b/Source/core/dom/Element.h
@@ -561,6 +561,10 @@ private:
     void clearElementFlag(ElementFlags);
     bool hasElementFlagInternal(ElementFlags) const;
 
+    bool isElementNode() const WTF_DELETED_FUNCTION; // Hide to catch useless calls.
+    bool isDocumentFragment() const WTF_DELETED_FUNCTION; // Hide to catch useless calls.
+    bool isDocumentNode() const WTF_DELETED_FUNCTION; // Hide to catch useless calls.
+
     void styleAttributeChanged(const AtomicString& newStyleString, AttributeModificationReason);
 
     void updatePresentationAttributeStyle();