Avoid blinking on first visit with service worker

render_with_wb.js

/*
 * When we have a workbox we must be sure to just render the
 * app when we assert that we are running the latest version.
 * Otherwise the user can start interacting with the app and
 * right after an update arrives and the page is reloaded.
 */
if (wb != null) {
  wb.active
    .then((serviceWorker) => {
      /* When the service worker active is not controlling the
       * current page, we trigger a page reload. So we should
       * not render the app to avoid the page blinking. */
      if (navigator.serviceWorker.controller === serviceWorker) {
        renderApp();
        return;
      }
      setTimeout(() => {
        const error = new Error('Page did not reload when expected');
        logException('New service worker must trigger a page reload', error);
        renderApp();
      }, 500);
    })
    .catch((error) => {
      logException('Error resolving active service worker', error);
      renderApp();
    });
} else {
  renderApp();
}