chromium/chrome/test/data/media/picture-in-picture/documen_picture_in_picture_pixel_test.html

<!DOCTYPE html>
<head>
<meta charset="utf-8">
<title>Document Picture-in-Picture</title>
</head>
<body>
</body>
<script>
    async function createDocumentPipWindow({ width = 300, height = 300 } = {}) {
        await documentPictureInPicture.requestWindow({ width: width, height: height, });
        return true;
    }
</script>