code: function () {
              if (this._storage) {
                  this._removeOldCache();
                  this._storage.setItem(this._storageKey, this._cache);
                  this._storage.$dispose();
                  this._storage = null;
              }
              ariaUtilsEvent.removeListener(Aria.$window, "unload", this._saveCacheCB);
          }
docs: Save the states that are still valid and needed in order to support page refresh and external navigation.
  Called on window unload.
  @protected