function assertNotBadBrElements(html) {
  if (userAgent.IE) {
    assertNotContains('There should not be <br> elements', '<br', html);
  } else {
    assertFalse(
        'There should not be <br> elements, except ones to prevent ' +
            '<div>s from collapsing' + html,
        /(?!<div>)<br>(?!<\/div>)/.test(html));
  }
}
Assert that only BR elements expected to persist after convertBreaksToDivs_
are in the HTML.