function matchIosWebview() {
  // Apple-based browsers don't support navigator.userAgentData yet, so use
  // navigator.userAgent.
  // iOS Webview does not show up as Chrome or Safari.
  return (util.matchUserAgent('iPad') || util.matchUserAgent('iPhone')) &&
      !matchSafari() && !matchChrome() && !matchCoast() && !matchFirefox() &&
      util.matchUserAgent('AppleWebKit');
}
@return {boolean} Whether the user's browser is iOS Webview.