[XHR] setRequestHeader and redirects

Hi,

currently, the XHR specification doesn't address how browsers are 
supposed to handle setRequestHeader when redirects are involved - 
http://www.w3.org/TR/XMLHttpRequest/#infrastructure-for-the-send-method 
does not say much at all.

Can we get a clarification in the spec on whether the browser is 
supposed to forward the user-set request headers to the redirect target 
or not? (Assuming, of course, that the target is an HTTP URI as well)

(Firefox currently doesn't forward the headers, but there's a patch to 
do so. https://bugzilla.mozilla.org/show_bug.cgi?id=553888)

-christian