Detach Event Listener Properties before moving Node.

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

Index: third_party/WebKit/Source/core/dom/Node.cpp
diff --git a/third_party/WebKit/Source/core/dom/Node.cpp b/third_party/WebKit/Source/core/dom/Node.cpp
index caf5618827c3424f3f6e8939958d3761287ee1f4..5a58300fb8881e1d3f52588d04f0b564c9939951 100644
--- a/third_party/WebKit/Source/core/dom/Node.cpp
+++ b/third_party/WebKit/Source/core/dom/Node.cpp
@@ -1808,6 +1808,16 @@ ExecutionContext* Node::getExecutionContext() const {
   return document().contextDocument();
 }
 
+void Node::willMoveToNewDocument(Document& oldDocument, Document& newDocument) {
+  if (oldDocument == newDocument)
+    return;
+
+  if (oldDocument.frameHost()) {
+    oldDocument.frameHost()->eventHandlerRegistry().didMoveOutOfFrameHost(
+        *this);
+  }
+}
+
 void Node::didMoveToNewDocument(Document& oldDocument) {
   TreeScopeAdopter::ensureDidMoveToNewDocumentWasCalled(oldDocument);
 
@@ -1820,14 +1830,10 @@ void Node::didMoveToNewDocument(Document& oldDocument) {
   }
 
   oldDocument.markers().removeMarkers(this);
-  if (oldDocument.frameHost() && !document().frameHost())
-    oldDocument.frameHost()->eventHandlerRegistry().didMoveOutOfFrameHost(
-        *this);
-  else if (document().frameHost() && !oldDocument.frameHost())
+  if (document().frameHost()) {
+    DCHECK_NE(document().frameHost(), oldDocument.frameHost());

[bokan, 2017/01/13 18:35:10]

Can we assume this in general? What if you move between documents in the same
FrameHost? My comment was about avoiding the whole removing and adding to
eventHandlerRegistry if it's not going to change.

[wjmaclean, 2017/01/13 20:04:24]

Ha ha ... apparently not according to the bots!

But now I better understand what you intended, so I'm running a revised patch on
the bots.

     document().frameHost()->eventHandlerRegistry().didMoveIntoFrameHost(*this);
-  else if (oldDocument.frameHost() != document().frameHost())
-    EventHandlerRegistry::didMoveBetweenFrameHosts(
-        *this, oldDocument.frameHost(), document().frameHost());
+  }
 
   if (const HeapVector<TraceWrapperMember<MutationObserverRegistration>>*
           registry = mutationObserverRegistry()) {