Why can't it be based of Chrome's version number? If you know the version number at the time of release then you can say only use the same runtime if there's on

Why can't it be based of Chrome's version number? If you know the version number at the time of release then you can say only use the same runtime if there's only a revision version difference, else you can use it's own run time. That packaged with auto-updates for the app to that developers can push updated builds every month or so should be fine.