It's not just google properties, the Strict Transport Security sectionof the chromium dev docs [1] lists multiple properties they do this for (for example, twitter and paypal), and it appears you can specify your own as well through the command line (and probably elsewhere).
I believe patio meant Google/Mozilla going to the CA and saying 'You duplicated our cert, you better explain or we will stop trusting you in our browsers'. Which would end the CA, of course. As they deserve to.
I took it as an implication that Google properties were getting special treatment by Chrome. I'm not sure how Chrome blacklisting a CA could be construed as anti-trust, even if it essentially killed the CA, because there's plenty of healthy competition in the browser space. They could just switch to Firefox, and not even lose the extra protections they were getting since Firefox pins google property certs as well.
[1]: http://dev.chromium.org/sts