Detach Event Listener Properties before moving Node.

third_party/WebKit/Source/core/dom/TreeScopeAdopter.cpp

 /*
  * 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, 2008, 2009, 2010, 2011 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2011 Google Inc. All rights reserved.
@@ skipping 117 matching lines @@
     Document& oldDocument,
     Document& newDocument) const {
   DCHECK_NE(oldDocument, newDocument);
 
   if (node.hasRareData()) {
     NodeRareData* rareData = node.rareData();
     if (rareData->nodeLists())
       rareData->nodeLists()->adoptDocument(oldDocument, newDocument);
   }
 
+  // TODO(wjmaclean): It seems weird here that oldDocument !=(in general)
+  // node.document(). I'd like to understand why, as it seems clinky passing
+  // oldDocument in the call to node.willMoveToNewDocument().

[bokan, 2017/01/04 23:33:27]

This was the first question I had above, why can't we just use node.document()
since "willMove" implies it hasn't moved yet. The fact that we pass in an
|oldDocument| to this method on TreeScopeAdapter seems suspect to me. 

+  node.willMoveToNewDocument(oldDocument);
   oldDocument.moveNodeIteratorsToNewDocument(node, newDocument);
 
   if (node.getCustomElementState() == CustomElementState::Custom) {
     Element& element = toElement(node);
     CustomElement::enqueueAdoptedCallback(&element, &oldDocument, &newDocument);
   }
 
   if (node.isShadowRoot())
     toShadowRoot(node).setDocument(newDocument);
 
 #if DCHECK_IS_ON()
   didMoveToNewDocumentWasCalled = false;
   oldDocumentDidMoveToNewDocumentWasCalledWith = &oldDocument;
 #endif
 
   node.didMoveToNewDocument(oldDocument);
 #if DCHECK_IS_ON()
   DCHECK(didMoveToNewDocumentWasCalled);
 #endif
 }
 
 }  // namespace blink