Detach Event Listener Properties before moving Node.

third_party/WebKit/Source/core/dom/Node.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) 2004-2011, 2014 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 849 matching lines @@
     CreateDocumentFragment = CreateContainer | IsDocumentFragmentFlag,
     CreateHTMLElement = CreateElement | IsHTMLFlag,
     CreateSVGElement = CreateElement | IsSVGFlag,
     CreateDocument = CreateContainer | IsConnectedFlag,
     CreateInsertionPoint = CreateHTMLElement | IsInsertionPointFlag,
     CreateEditingText = CreateText | HasNameOrIsEditingTextFlag,
   };
 
   Node(TreeScope*, ConstructionType);
 
+  virtual void willMoveToNewDocument(Document& oldDocument);
   virtual void didMoveToNewDocument(Document& oldDocument);
 
   void addedEventListener(const AtomicString& eventType,
                           RegisteredEventListener&) override;
   void removedEventListener(const AtomicString& eventType,
                             const RegisteredEventListener&) override;
   DispatchEventResult dispatchEventInternal(Event*) override;
 
   static void reattachWhitespaceSiblingsIfNeeded(Text* start);
 
@@ skipping 137 matching lines @@
 }  // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showNode(const blink::Node*);
 void showTree(const blink::Node*);
 void showNodePath(const blink::Node*);
 #endif
 
 #endif  // Node_h