WP_Customize_Manager::handle_changeset_trash_request()

	public function handle_changeset_trash_request() {
		if ( ! is_user_logged_in() ) {
			wp_send_json_error( 'unauthenticated' );
		}

		if ( ! $this->is_preview() ) {
			wp_send_json_error( 'not_preview' );
		}

		if ( ! check_ajax_referer( 'trash_customize_changeset', 'nonce', false ) ) {
			wp_send_json_error( array(
				'code' => 'invalid_nonce',
				'message' => __( 'There was an authentication problem. Please reload and try again.' ),
			) );
		}

		$changeset_post_id = $this->changeset_post_id();

		if ( ! $changeset_post_id ) {
			wp_send_json_error( array(
				'message' => __( 'No changes saved yet, so there is nothing to trash.' ),
				'code' => 'non_existent_changeset',
			) );
			return;
		}

		if ( $changeset_post_id && ! current_user_can( get_post_type_object( 'customize_changeset' )->cap->delete_post, $changeset_post_id ) ) {
			wp_send_json_error( array(
				'code' => 'changeset_trash_unauthorized',
				'message' => __( 'Unable to trash changes.' ),
			) );
		}

		if ( 'trash' === get_post_status( $changeset_post_id ) ) {
			wp_send_json_error( array(
				'message' => __( 'Changes have already been trashed.' ),
				'code' => 'changeset_already_trashed',
			) );
			return;
		}

		$r = $this->trash_changeset_post( $changeset_post_id );
		if ( ! ( $r instanceof WP_Post ) ) {
			wp_send_json_error( array(
				'code' => 'changeset_trash_failure',
				'message' => __( 'Unable to trash changes.' ),
			) );
		}

		wp_send_json_success( array(
			'message' => __( 'Changes trashed successfully.' ),
		) );
	}