Better is ChromeOS 67 enables running your own containers without having to put CB in developer.
It uses the KVM to run a second Linux kernel. So you will be able to use GNU/Linux applications including Steam. More to be shared at Google IO this year.
vmc start dev
start_container.sh --container_name stretch --user <yourusername> --shell
That should drop you into a shell in a debian stretch distro. You can install packages and launch them. I haven't figured out if there's a way to pin them to the shelf yet and launch that way.
It uses the KVM to run a second Linux kernel. So you will be able to use GNU/Linux applications including Steam. More to be shared at Google IO this year.