Make AttachBehavior a required argument.

Source/core/dom/ContainerNode.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010, 2011 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 81 matching lines @@
 
     // ParentNode interface API
     PassRefPtr<HTMLCollection> children();
     Element* firstElementChild() const;
     Element* lastElementChild() const;
     unsigned childElementCount() const;
 
     unsigned childNodeCount() const;
     Node* childNode(unsigned index) const;
 
-    void insertBefore(PassRefPtr<Node> newChild, Node* refChild, ExceptionState& = ASSERT_NO_EXCEPTION, AttachBehavior = AttachNow);
-    void replaceChild(PassRefPtr<Node> newChild, Node* oldChild, ExceptionState& = ASSERT_NO_EXCEPTION, AttachBehavior = AttachNow);
+    void insertBefore(PassRefPtr<Node> newChild, Node* refChild, ExceptionState&, AttachBehavior);
+    void replaceChild(PassRefPtr<Node> newChild, Node* oldChild, ExceptionState&, AttachBehavior);
     void removeChild(Node* child, ExceptionState& = ASSERT_NO_EXCEPTION);
-    void appendChild(PassRefPtr<Node> newChild, ExceptionState& = ASSERT_NO_EXCEPTION, AttachBehavior = AttachNow);
+    void appendChild(PassRefPtr<Node> newChild, ExceptionState&, AttachBehavior);
 
     // These methods are only used during parsing.
     // They don't send DOM mutation events or handle reparenting.
     // However, arbitrary code may be run by beforeload handlers.
     void parserAppendChild(PassRefPtr<Node>);
     void parserRemoveChild(Node*);
     void parserInsertBefore(PassRefPtr<Node> newChild, Node* refChild);
 
     void removeChildren();
     void takeAllChildrenFrom(ContainerNode*);
@@ skipping 229 matching lines @@
         m_node->resumePostAttachCallbacks();
     }
 
 private:
     ContainerNode* m_node;
 };
 
 } // namespace WebCore
 
 #endif // ContainerNode_h