Looks like it's an open source project by individuals who also happen to be employed by Google, and the extent of Google's involvement is the copyright.
Edit: looking at the LICENSE file, scratch that, it appears Google doesn't even own the copyright.
Not really. Google owns the copyright for all code contributed by Google employees on Google time, and currently they are the only copyright holder [1].
In order to contribute you have to sign the standard Google Contributor License Agreement (either [0] or the corporate version) which gives Google a perpetual irrevocable copyright and patent license. Since the project is BSD licensed anyway, unless you're contributing something you intend to patent, you're giving Google nothing by signing the CLA: you still own the actual copyright. (Based on my skimming the agreement; IANAL)
Edit: looking at the LICENSE file, scratch that, it appears Google doesn't even own the copyright.