isHtmlElementOfType = (value, tagName) => {
  return goog.isObject(value) && isHtmlElement(value) &&
      // Some uncommon JS environments (e.g. Cobalt 9) have issues with tag
      // capitalization.
      (/** @type {!HTMLElement} */ (value).tagName.toUpperCase() ===
       tagName.toString());
}
Determines if a value is a DOM HTML Element of a specified tag name. For
modern browsers, tags that provide access to special DOM APIs are implemented
as special subclasses of HTMLElement.
@param {*} value
@param {!TagName} tagName
@return {boolean}