chromium/third_party/blink/web_tests/http/tests/security/cookies/resources/cross-origin-set-cookies.php

<?php
header('Content-Type: text/html; charset=UTF-8');
header('Set-Cookie: ' . $_GET['SetCookie']);
header('Access-Control-Allow-Origin: http://127.0.0.1:8000');
header('Access-Control-Allow-Credentials: true');
?>