As noted in bug 968923 comment 95, CSS property aliases & shorthands can't yet be counted, with our current UseCounter infrastructure. Filing this bug on making them work. (I think the problem is that our style-system UseCounters currently operate on the *output* of nsCSSParser, and aliases/shorthands are processed away into their unaliased/longform versions by the time we've finished making that output.)

Note: I have a patch in bug 1231682 (labeled "part 1") that makes us keep track of the *actual author-provided property* that we're parsing at any given time, in a special member-variable. That patch didn't end up being something that we needed on that bug, but it might come in handy over here.