extensions.registerSchemaAPI("sessions", "addon_parent", context => {
  let {extension} = context;
  return {
    sessions: {
      restore: function(sessionId) {
          let recentlyClosed = getRecentlyClosed(1, extension)[0];
          if (recentlyClosed.window) {
            let window = SessionStore.undoCloseWindow(0);
            promiseObserved("sessionstore-single-window-restored",
              subject => subject == window).then(() => {
              sessionObj.lastModified = Date.now();
              sessionObj.window = WindowManager.convert(extension, window, {populate: true});
              return Promise.resolve([sessionObj]);
            });
          } else {
            // ignore this part for now
            let window = WindowManager.getWindow(recentlyClosed.tab.windowId);
            dump(window);
            let tab = SessionStore.undoCloseTab(window, 0);
            sessionObj.lastModified = Date.now();
            sessionObj.tab = TabManager.for(extension).convert(tab);
          }
        }
        // if (sessionObj) {
        //   return Promise.resolve([sessionObj]);
        // }
        // return Promise.reject({message: `Could not restore object using sessionId ${sessionId}.`});
      },
    },
  };
});