diff --git a/dom/events/EventListenerManager.cpp b/dom/events/EventListenerManager.cpp
index 25f8abad6148..74047b93ad5a 100644
--- a/dom/events/EventListenerManager.cpp
+++ b/dom/events/EventListenerManager.cpp
@@ -292,14 +292,11 @@ EventListenerManager::AddEventListenerInternal(
     nsContentUtils::LegacyIsCallerChromeOrNativeCode();
 
   // Detect the type of event listener.
-  nsCOMPtr<nsIXPConnectWrappedJS> wjs;
   if (aFlags.mListenerIsJSListener) {
     MOZ_ASSERT(!aListenerHolder.HasWebIDLCallback());
     listener->mListenerType = Listener::eJSEventListener;
   } else if (aListenerHolder.HasWebIDLCallback()) {
     listener->mListenerType = Listener::eWebIDLListener;
-  } else if ((wjs = do_QueryInterface(aListenerHolder.GetXPCOMCallback()))) {
-    listener->mListenerType = Listener::eWrappedJSListener;
   } else {
     listener->mListenerType = Listener::eNativeListener;
   }
@@ -1715,8 +1712,6 @@ EventListenerManager::MarkForCC()
       if (typedHandler.HasEventHandler()) {
         typedHandler.Ptr()->MarkForCC();
       }
-    } else if (listener.mListenerType == Listener::eWrappedJSListener) {
-      xpc_TryUnmarkWrappedGrayObject(listener.mListener.GetXPCOMCallback());
     } else if (listener.mListenerType == Listener::eWebIDLListener) {
       listener.mListener.GetWebIDLCallback()->MarkForCC();
     }
diff --git a/dom/events/EventListenerManager.h b/dom/events/EventListenerManager.h
index b0847055b86b..7ac5e0181ad1 100644
--- a/dom/events/EventListenerManager.h
+++ b/dom/events/EventListenerManager.h
@@ -189,10 +189,13 @@ public:
 
     enum ListenerType : uint8_t
     {
+      // No listener.
       eNoListener,
+      // A generic C++ implementation of nsIDOMEventListener.
       eNativeListener,
+      // An event handler attribute using JSEventHandler.
       eJSEventListener,
-      eWrappedJSListener,
+      // A scripted EventListener.
       eWebIDLListener,
     };
     ListenerType mListenerType;