--- a/dom/media/webaudio/AudioDestinationNode.cpp
+++ b/dom/media/webaudio/AudioDestinationNode.cpp
@@ -408,20 +408,21 @@ AudioDestinationNode::DestroyMediaStream
     MediaStreamGraph::DestroyNonRealtimeInstance(graph);
   }
   AudioNode::DestroyMediaStream();
 }
 
 void
 AudioDestinationNode::NotifyMainThreadStreamFinished()
 {
+  MOZ_ASSERT(NS_IsMainThread());
   MOZ_ASSERT(mStream->IsFinished());
 
   if (mIsOffline) {
-    NS_DispatchToCurrentThread(
+    AbstractMainThread()->Dispatch(
       NewRunnableMethod("dom::AudioDestinationNode::FireOfflineCompletionEvent",
                         this,
                         &AudioDestinationNode::FireOfflineCompletionEvent));
   }
 }
 
 void
 AudioDestinationNode::FireOfflineCompletionEvent()