--- a/dom/media/imagecapture/CaptureTask.cpp
+++ b/dom/media/imagecapture/CaptureTask.cpp
@@ -186,12 +186,15 @@ CaptureTask::PostTrackEndEvent()
       return NS_OK;
     }
 
   protected:
     RefPtr<CaptureTask> mTask;
   };
 
   IC_LOG("Got MediaStream track removed or finished event.");
-  NS_DispatchToMainThread(new TrackEndRunnable(this));
+  nsCOMPtr<nsIRunnable> event = new TrackEndRunnable(this);
+  SystemGroup::Dispatch("CaptureTask::TaskComplete",
+                        TaskCategory::Other,
+                        event.forget());
 }
 
 } // namespace mozilla