Chrome has certificate pinning, see http://blog.chromium.org/2011/06/new-chromium-security-featu...:

"In addition in Chromium 13, only a very small subset of CAs have the authority to vouch for Gmail (and the Google Accounts login page). This can protect against recent incidents where a CA has its authority abused, and generally protects against the proliferation of signing authority."

(disclaimer: I work for Chrome but not on these features.)