turnOnControls () {
        if (this._root) {
            const attribute = this.controlsUseVisibility() ? 'visibility' : 'display';
            this.selectAll('.reset').style(attribute, null);
            this.selectAll('.filter').text(this._filterPrinter(this.filters())).style(attribute, null);
        }
        return this;
    }
Turn on optional control elements within the root element. dc currently supports the
following html control elements.
* root.selectAll('.reset') - elements are turned on if the chart has an active filter. This type
of control element is usually used to store a reset link to allow user to reset filter on a
certain chart. This element will be turned off automatically if the filter is cleared.
* root.selectAll('.filter') elements are turned on if the chart has an active filter. The text
content of this element is then replaced with the current filter value using the filter printer
function. This type of element will be turned off automatically if the filter is cleared.
@returns {BaseMixin}