before-unload-with-subframes-parent.html

<!DOCTYPE html>
<html>
<body>
<iframe src="before-unload-in-subframe-child.html"></iframe>
<iframe src="before-unload-in-subframe-child.html"></iframe>
<iframe src="before-unload-in-subframe-child.html"></iframe>
</body>
</html>

chromium/third_party/blink/web_tests/fast/events/resources/before-unload-with-subframes-parent.html