Right now, if we have a bunch of table cells that all share ComputedValues, their anonymous block boxes still won't share anything, though they could do so. This can use a noticeable amount of memory; see data in bug 1367862 comment 1 and bug 1367862 comment 2.
Moved the anonymous box stuff into bug 1368291, since it's the same as text. Lazy pseudos will require checking the rule node pointer, which we'll have soon.
(In reply to Bobby Holley (:bholley) (busy with Stylo) from comment #1) > Moved the anonymous box stuff into bug 1368291 Err, the anonymous box stuff is bug 1368290.