static parseXml(data, expectedRootElemName, includeParent = false) {
    const xmlString = shaka.util.StringUtils.fromBytesAutoDetect(data);
    return shaka.util.TXml.parseXmlString(
        xmlString, expectedRootElemName, includeParent);
  }
Parse some data
@param {BufferSource} data
@param {string=} expectedRootElemName
@param {boolean=} includeParent
@return {shaka.extern.xml.Node | null}