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 $settings: The widget settings.
Overrides PluginBase::__construct
public function __construct($plugin_id, array $plugin_definition, FieldInstance $instance, array $settings) {
parent::__construct(array(), $plugin_id, $plugin_definition);
$this->instance = $instance;
$this->field = field_info_field($instance['field_name']);
$this->settings = $settings;
}