docs: function DOMWalker_modalWindowHelper(controller) {
      let domWalker = new DOMWalker(controller,
                                    persisted.modalInfos.callbackFilter,
                                    persisted.modalInfos.callbackNodeTest,
                                    persisted.modalInfos.callbackResults);
      domWalker.walk(persisted.modalInfos.ids,
                     controller.window.document.documentElement,
                     persisted.modalInfos.waitFunction);
  
      delete persisted.modalInfos;
  
      controller.window.close();
    }