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..6edd1da5ce890c9c2071d4330c9a780ac63490e2 100644
--- a/third_party/WebKit/Source/core/dom/TreeScopeAdopter.cpp
+++ b/third_party/WebKit/Source/core/dom/TreeScopeAdopter.cpp
@@ -52,6 +52,10 @@ void TreeScopeAdopter::moveTreeToNewScope(Node& root) const {
     oldDocument.incDOMTreeVersion();
 
   for (Node& node : NodeTraversal::inclusiveDescendantsOf(root)) {
+    // Before node.document() changes, allow the node to do pre-move changes.

[bokan, 2017/01/12 16:54:48]

Please add a comment in TreeScopeAdopter::moveNodeToNewDocument that
node.document() may already have been changed and that's why oldDocument is
passed in.

[wjmaclean, 2017/01/13 17:40:30]

Done.

+    if (willMoveToNewDocument)
+      node.willMoveToNewDocument();
+
     updateTreeScope(node);
 
     if (willMoveToNewDocument) {