onships here.
      canContain['html'] = ['body', 'frameset', 'head'];
      canContain['head'] = [
          'base', 'command', 'link', 'meta', 'noscript', 'script', 'style',
          'title'];
      canContain['frameset'] = ['frame', 'frameset', 'noframes'];
      // TODO: do the same for the text content model.
      toSatisfy.satisfy();
    }
    displayJson(canContain, document.getElementById('can-contain-json'));
  }

  if (canContain instanceof Promise) {
    when(function () { run(newBlankObject())