A few months ago at Google I/O, Google demoed Android apps running on Chrome OS . Today, Google is making that demo a reality by launching " App Runtime for Chrome (Beta) ."

Google is not opening the floodgates and loading a full Play Store with every Chromebook; instead, it is manually bringing over certain apps. "Over the coming months, we’ll be working with a select group of Android developers to add more of your favorite apps so you’ll have a more seamless experience across your Android phone and Chromebook," the company said in its announcement.

For now, the feature is launching with four compatible apps: Duolingo, Evernote, Sight Words, and Vine. One app not mentioned was Flipboard, which was demoed at I/O.

We were curious about just how this worked, so we got some more details from a Google spokesperson:

The app code is all running on top of the Chrome platform, specifically inside of Native Client. In this way the ARC (App Runtime for Chrome) apps run in the same environment as other apps you can download from the Chrome Web Store, even though they are written on top of standard Android APIs. The developers do not need to port or modify their code, though they often choose to improve it to work well with the Chromebook form factor (keyboard, touchpad, optional touchscreen, etc).

There is no porting required. It seems that Google has built an entire Android stack into Chrome OS using Native Client. Both OSes are based on Linux, making libraries, the app framework, and the Android runtime the big differences. We wonder if it's using Dalvik or ART.

Android apps show up in the launcher just like any other Chrome app, and apps are downloaded from the Chrome Web Store. Portability like this has always been one of the benefits of writing to a virtual machine, and now it seems Google is really starting to take advantage of it.