From what I've heard, there's now an ability to run android apps in ChromeOS with Google's Arc Welder:
https://developer.chrome.com/apps/getstarted_arcI don't have a ChromeOS device, however, I've tried using this tool with a slightly modified build of OpenXcom for Android (basically, I've put all assets into the app package), and it seemed to work on my laptop in Chrome. There were some issues, however (most notably, mouse wheel was misinterpreted, and resizing the window crashed/restarted the game), but it worked overall.
Unfortunately, I can't redistribute the modified package, but it's really easy to build one yourself! Just follow the instructions for the Android port build (
https://github.com/sfalexrog/openxcom-android). Be sure to put the game data into the
app/src/main/jni/OpenXcom/bin subfolders, because right now I don't think an ARC app can access local filesystem.