undefined as request body for ajax calls in Chrome

undefined as request body for ajax calls in Chrome

(reposted, the original was having problems)

There's a ticket open for this issue for 1.3.2, but I've encountered the problem in 1.4.1 as well as the nightly. I've updated the ticket with what I think the root cause is -- a Chrome bug -- and my proposed solution.

I believe the simplest fix is setting jQuery.ajaxSettings.data to null instead of leaving it undefined. Comments?