[pp.int.general] Google released source code for a Chrome OpenPGP extension.

[Cal.]

http://googleonlinesecurity.blogspot.it/2014/06/making-end-to-end-encryption-easier-to.html?m=1

They say it's open for scrutiny, and not yet ready for public use.

This is the repo: https://code.google.com/p/end-to-end/