This completely misses the point. There's absolutely no benefit here... You might as well write in JavaScript/Node.js instead.
We compile to JS for the web because we can't control which browser the user uses. However if we're building for a desktop app which is just a browser being packaged with the app code...We can choose which browser is being bundled with everything. So we should be using Dart VM. The performance is so much better.
Otherwise, we aren't solving any problems. We already can build desktop apps with JavaScript. There's no real sense in using Dart to do that.
I'm not super familiar with the internals of Appjs.com and how it uses CEF and such...But I'd be interested in learning more because I think that same approach should work for Dart and Chrome/Dartium with the Dart VM packed in there.
This will be super super cool stuff.
....After some more reading I realize Chrome Apps will do all this, but Dart VM is not yet integrated. Can't wait for that!