Test case for mathiasbynens/CSS.escape#2 and WebKit issue 149175.

Open DevTools and run CSS.escape to print the value.

WebKit Nightly: Upon first visit (empty cache) it is possible that it prints undefined rather than the function's body.

Note: The issue cannot be reproduced reliably. Sometimes hitting Command R will make CSS.escape actually hold the function, sometimes you need Command Shift R. Usually cleaning the cache and or restarting the browser before opening this page will make WebKit (or JavaScriptCore, or whatever) exhibit this behavior.