I think you're confusing Chromebooks for Android devices; running non-Google operating systems on Chromebooks is very-well-documented.

I think you're also missing the parent commenter's point: that even on ChromeOS (via Crouton), his daughter's newly-learned skills will be much more universally-applicable, since she's working directly with free development tools available universally and on virtually all modern platforms (plus Windows) instead of working with toolchains specific to only one not-really-all-that-modern platform.