This bug was filed from the Socorro interface and is report bp-5d722e08-0aa1-4151-a1cd-fbdff2130131 . ============================================================= happened when profiling a very JS-heavy demo
Seeing this on another demo now too (can't share source).
It's likely a duplicate of bug 832812.
Visiting http://productforums.google.com/d/topic/chat/5bE-mrVrP3A on the 2/10 nightly gives me a completely reproducible crash as the page loads.