WP_Customize_Widgets::register_settings() WordPress Method

	public function register_settings() {
		$widget_setting_ids   = array();
		$incoming_setting_ids = array_keys( $this->manager->unsanitized_post_values() );
		foreach ( $incoming_setting_ids as $setting_id ) {
			if ( ! is_null( $this->get_setting_type( $setting_id ) ) ) {
				$widget_setting_ids[] = $setting_id;
			}
		}
		if ( $this->manager->doing_ajax( 'update-widget' ) && isset( $_REQUEST['widget-id'] ) ) {
			$widget_setting_ids[] = $this->get_setting_id( wp_unslash( $_REQUEST['widget-id'] ) );
		}

		$settings = $this->manager->add_dynamic_settings( array_unique( $widget_setting_ids ) );

		if ( $this->manager->settings_previewed() ) {
			foreach ( $settings as $setting ) {
				$setting->preview();
			}
		}
	}