generateRows = function() {
    var rowIds = [
      200, 9, 1, 3, 2, 20, 100
    ];
    var CONTENTS = {'scan': 'rowid'};
    return rowIds.map(function(rowId) {
      return new lf.Row(rowId, CONTENTS);
    });
  }
Generates a set of rows where they are on purpose not sorted with respect
to the row ID and with the larger rowID in position 0.
@return {!Array<!lf.Row>}