third_party/subscriptions-project/swg.js
/**
   * Handler when close action is triggered, will pop history state to close
   * the iframe.
   * @param {{container: !Element, iframe:!HTMLIFrameElement}} containerAndFrame
   * @private
   */
Handler when close action is triggered, will pop history state to close
the iframe.
Handler when close action is triggered will pop history state to close the iframe .
closeActionHandler_(containerAndFrame) {
    if (containerAndFrame['container'].parentNode) {
      history.back();
    }
  }
closeActionHandler_ ( containerAndFrame ) { if ( containerAndFrame [ 'container' ] . parentNode ) { history . back ( ) ; } }
Handler when close action is triggered, will pop history state to close
 the iframe.
Handler when close action is triggered will pop history state to close the iframe .
// Close action only when container is still attached to the page.