Issue #3257300 by diaodiallo: Add schema so that view can be properly translated

views.style.charts_highcharts_drilldown:

  type: views_style

  label: 'Chart highcharts drilldown'

  mapping:

    chart_settings:

      type: charts_config

      label: 'Settings'

    fields_series_field:

      type: string

      label: 'Series Field'

    fields_drilldown_series_field:

      type: string

      label: 'Drilldown Field'

    fields_data_field:

      type: string

      label: 'Data Field'

    fields_operator:

      type: string

      label: 'Operator Field'

 */

class ChartsDrilldownPluginStyleChart extends ChartsPluginStyleChart {

  /**

   * {@inheritdoc}

   */

  protected function defineOptions() {

    $options = parent::defineOptions();

    $options['fields_series_field'] = ['default' => ''];

    $options['fields_drilldown_series_field'] = ['default' => ''];

    $options['fields_data_field'] = ['default' => ''];

    $options['fields_operator'] = ['default' => ''];

    return $options;

  }

  /**

   * {@inheritdoc}

   */