How to hide close button on infowindow in ionic2

Ionic Framework ionic-v3
1

to hide close button on infowindow,in options of infowindow I add buttons property but it shows error.how can I do that.

addInfoWindow(marker, content) {
    content='<p align="center">'+content+'</p>';
    let infoWindow = new google.maps.InfoWindow({
      content: content,
      buttons: { 
               close: { visible: false }  
            } 
    });