I'm seeing a lot of speculation about a shadowy hidden agenda in these comments, but based on my time at Google I'd say it's very possible there is no overall strategy here. The only prereq is that someone wanted to do this and was able to get buy in from their director. Would it make sense for Google to not maintain two separate OSes that both strive to support the other OS's software? Sure, maybe it would. But that hasn't stopped Google before from having multiple products that do the same thing for no good reason. And there are likely a lot of folks who have built little fiefdoms (or at least domain expertise) within ChromeOS who want to see that investment maintained.

And remember, there's also fuchsia, supposedly a future replacement OS but who knows what that's going to turn into if anything.

To folks who think this is a way to "kill Linux support" on Android, I don't know what to tell you. Almost nobody uses those features and they're not a threat to Google; I can't imagine anyone is thinking "how can we invest developer time to get rid of this?" and being taken seriously.