deserialize = function(tableSchema, obj) {
    return tableSchema.deserializeRow({
      'id': lf.Row.getNextId(),
      'value': obj
    });
  }
Creates a MockDataGenerator with a fixed set of data.
@param {!lf.schema.Database} schema
@param {!lf.testing.hrSchema.MockDataGenerator.ExportData} data
@return {!lf.testing.hrSchema.MockDataGenerator}