Constructs a WidgetBase object.
array $plugin_id: The plugin_id for the widget.
array $plugin_definition: The plugin implementation definition.
\Drupal\field\Plugin\Core\Entity\FieldInstance $instance: The field instance to which the widget is associated.
array $settings: The widget settings.
Overrides WidgetBase::__construct
public function __construct($plugin_id, array $plugin_definition, FieldInstance $instance, array $settings) {
parent::__construct($plugin_id, $plugin_definition, $instance, $settings);
// Reset internal pointer since we're dealing with objects now.
reset($this->field['columns']);
$this->column = key($this->field['columns']);
}