static getEeMapType(mapUrlFormat) {
    var eeMapOptions = {
      getTileUrl: function(tile, zoom) {
        // We haven't loaded the ee client library, so we process the template
        // explicitly instead of calling ee.data.getTileUrl(mapid, x, y, zoom).
        return mapUrlFormat.replace('{x}', tile.x)
            .replace('{y}', tile.y)
            .replace('{z}', zoom);
      },
      tileSize: new google.maps.Size(256, 256)
    };
    return new google.maps.ImageMapType(eeMapOptions);
  }
Generates a Google Maps map type (or layer) for the passed-in EE map id.
See:
https://developers.google.com/maps/documentation/javascript/maptypes#ImageMapTypes
@param {string} mapUrlFormat The Earth Engine map url template.
@return {google.maps.ImageMapType} A Google Maps ImageMapType object for
    the EE map with the given ID and token.