Bug 1264383 - makeFilteringListener breaks eventremoval with shims. r=mconley

toolkit/components/addoncompat/RemoteAddonsParent.jsm

@@ -587,10 +587,6 @@ EventTargetParent.init();
 var filteringListeners = new WeakMap();
 function makeFilteringListener(eventType, listener)
 {
-  if (filteringListeners.has(listener)) {
-    return filteringListeners.get(listener);
-  }
-
   // Some events are actually targeted at the <browser> element
   // itself, so we only handle the ones where know that won't happen.
   let eventTypes = ["mousedown", "mouseup", "click"];
@@ -598,6 +594,10 @@ function makeFilteringListener(eventType, listener)
     return listener;
   }
 
+  if (filteringListeners.has(listener)) {
+    return filteringListeners.get(listener);
+  }
+
   function filter(event) {
     let target = event.originalTarget;
     if (target instanceof Ci.nsIDOMXULElement &&