Well I can't prove it, but I first noticed this about three weeks ago and I'm 100% positive they haven't changed anything since then. They may have used JS redirects further back in the past, I'm not sure.
Override your user agent with Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html). You'll see that both a regular user and a google bot are getting served a 301. So I don't think it's cloaking by definition anymore. However if you go to:
Ya, I did the user agent testing three weeks ago and got the same results I am getting today. I'm certainly not keeping close track of them, so maybe they did change something, but everything I see is 1:1 as it was when I first saw it. Perhaps they are detecting Googlebot via IP instead of user agent. I dunno.
http://webcache.googleusercontent.com/search?q=cache:http://...
You'll see that you get redirected. But disable javascript in your dev tools, and you'll see that you no longer get redirected :)