I had a very tangential role in getting Google+ out the door (as in, I got pulled in for last-minute bugfixing and fixed a handful of bugs), and I've been working in the Google+ codebase for the last few weeks.

http://ssl.gstatic.com/gb/js/pwm_377e54339fe6909b01c5d023b52... uses goog.structs.SimplePool, so you know at least that part uses Closure, http://closure-library.googlecode.com/svn/docs/class_goog_st....

I'm pretty sure nostrademons works for google...