code: function announceAccessibleMessage(msg) {
    var element = document.createElement('div');
    element.setAttribute('aria-live', 'polite');
    element.style.position = 'relative';
    element.style.left = '-9999px';
    element.style.height = '0px';
    element.innerText = msg;
    document.body.appendChild(element);
    window.setTimeout(function() {
      document.body.removeChild(element);
    }, 0);
  }
docs: Add an accessible message to the page that will be announced to
  users who have spoken feedback on, but will be invisible to all
  other users. It's removed right away so it doesn't clutter the DOM.
  @param {string} msg The text to be pronounced.