Re: So really...
Where did you hear it is forked from Gentoo? Neither ChromeOS/ChromimumOS(the ChromeBook OS) nor GCP(https://en.wikipedia.org/wiki/Google_Cloud_Platform, the platform from this article) mention being a fork from an obscure Linux distro. Gentoo is a neat idea, and if you have 24 hours to build a system, it's pretty cool for what it accomplishes, but your information about it being the source is suspect. The only thing they share is a linux kernel at their core.
Let me put this another way; your assertion sounds odd, at best. I've never, EVER heard of this alleged fork, and the two Chrome OS pages on wikipedia, AND the GCP page do not mention Gentoo. And the Gentoo page does not mention Google. If you're from a different multiverse, then you are off by one. I suggest you reset your matter-paddle and try again, Rimmer!
EDIT: I see where you got confused: At the bottom of the Gentoo wikipedia entry; "Distributions using Gentoo's Portage system include CoreOS, Chrome OS, Chromium OS, and Ututo." Portage itself is the package management system for Gentoo, which is a port from the BSD Ports system and not even an original Gentoo device. Pay attention, people!