Bug 1072144 part 2. When UnregisterWorker tries to ScheduleWorker and that throws, just suppress the exception: there is no good place to report it anyway. r=khuey

dom/workers/RuntimeService.cpp

@@ -1666,6 +1666,9 @@ RuntimeService::UnregisterWorker(JSContext* aCx, WorkerPrivate* aWorkerPrivate)
 
   if (queuedWorker && !ScheduleWorker(aCx, queuedWorker)) {
     UnregisterWorker(aCx, queuedWorker);
+    // There's nowhere sane to report the exception from ScheduleWorker, if any,
+    // here.
+    JS_ClearPendingException(aCx);
   }
 }