function getClassesToAdd(columnStatesManager, column, showSortIndicator) {
  var cssClasses = [];

  if (showSortIndicator === false) {
    return cssClasses;
  }

  if (columnStatesManager.isColumnSorted(column) && columnStatesManager.getNumberOfSortedColumns() > 1) {
    cssClasses.push("".concat(COLUMN_ORDER_PREFIX, "-").concat(columnStatesManager.getIndexOfColumnInSortQueue(column) + 1));
  }

  return cssClasses;
}
Get CSS classes which should be added to particular column header.

@param {Object} columnStatesManager Instance of column state manager.
@param {Number} column Physical column index.
@param {Boolean} showSortIndicator Indicates if indicator should be shown for the particular column.
@returns {Array} Array of CSS classes.