I've been using 1-Click Shorten URL for about a month. It's a little clunky, since it depends on services provided by the dev's own web site. As of today, it first became glacially slow, then finally stopped working altogether (throws out a 502 Bad Gateway error). I wish I could find an extension that uses goo.gl and that actually works (I've tried the goo.gl URL extension, but it doesn't copy anything to the clipboard, despite claiming to do so).

Sigh. I guess this is life in a Quantum world...