Hide isXXX() type checking methods in subclasses

Source/core/dom/Text.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 50 matching lines @@
     Text(TreeScope& treeScope, const String& data, ConstructionType type)
         : CharacterData(treeScope, data, type)
     {
         ScriptWrappable::init(this);
     }
 
 private:
     virtual String nodeName() const OVERRIDE;
     virtual PassRefPtrWillBeRawPtr<Node> cloneNode(bool deep = true) OVERRIDE FINAL;
 
+    bool isTextNode() const WTF_DELETED_FUNCTION; // Hide to catch useless calls.
+
     bool needsWhitespaceRenderer();
 
     virtual PassRefPtrWillBeRawPtr<Text> cloneWithData(const String&);
 
 #ifndef NDEBUG
     virtual void formatForDebugger(char* buffer, unsigned length) const OVERRIDE;
 #endif
 };
 
 DEFINE_NODE_TYPE_CASTS(Text, isTextNode());
 
 } // namespace blink
 
 #endif // Text_h