Detach Event Listener Properties before moving Node.

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

Index: third_party/WebKit/Source/core/dom/TreeScopeAdopter.cpp
diff --git a/third_party/WebKit/Source/core/dom/TreeScopeAdopter.cpp b/third_party/WebKit/Source/core/dom/TreeScopeAdopter.cpp
index 8600f7773cf3b11aa8b994cf5d819644ce31eddf..d50eea1ba8022fff3262c09eea13246d49a12692 100644
--- a/third_party/WebKit/Source/core/dom/TreeScopeAdopter.cpp
+++ b/third_party/WebKit/Source/core/dom/TreeScopeAdopter.cpp
@@ -135,6 +135,10 @@ inline void TreeScopeAdopter::moveNodeToNewDocument(
       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) {