The Google-authored parts of Chromium are under a BSD license, which is even more permissive of proprietary derivatives than the Apache license Matthew discussed. Also, if you compare Google's CLA to Apache's, you might be be pleasantly surprised.
The short version: contributing under the Google CLA to a BSD-licensed or Apache-licensed Google project is much more like the Apache Software Foundation case than the Canonical case, despite Google being for-profit.
Full disclosure: I work for Google, but I'm not speaking for my employer and this is not legal advice, nor am I a lawyer. Google's license choices and Apache-style CLA text are not just my opinion as a Googler; feel free to look yourself and come to your own conclusions.
Re: google's CLA
The short version: contributing under the Google CLA to a BSD-licensed or Apache-licensed Google project is much more like the Apache Software Foundation case than the Canonical case, despite Google being for-profit.
Full disclosure: I work for Google, but I'm not speaking for my employer and this is not legal advice, nor am I a lawyer. Google's license choices and Apache-style CLA text are not just my opinion as a Googler; feel free to look yourself and come to your own conclusions.