loadFloatTile_(tileUrl, coord, tileId, div) {
    var tileRequest = goog.net.XmlHttp();
    tileRequest.open('GET', tileUrl, true);
    tileRequest.responseType = 'arraybuffer';
    tileRequest.onreadystatechange = goog.bind(function() {
      if (tileRequest.readyState === XMLHttpRequest.DONE &&
          tileRequest.status === 200) {
        var tileResponse = /** @type {Float32Array} */ (tileRequest.response);
        if (tileResponse) {
          var floatBuffer = new Float32Array(tileResponse);
          this.handleFloatTileLoaded_(floatBuffer, coord, tileId, div);
        } else {
          this.tilesFailed.add(tileId);
          throw new Error('Unable to request floating point array buffers.');
        }
      }
    }, this);
    tileRequest.send();
  }
Requests a floating point tile from the provided URL.
@param {string} tileUrl Tile URL
@param {google.maps.Point} coord Coordinates of the floating tile
@param {string} tileId Unique tile ID
@param {!Element} div The corresponding DIV element.
@private