Just checked it out, you're right. They actually explicitly said:
> In order to do what's best for our users and the web, and not just Google Chrome, we will focus our web efforts on compiling Dart to JavaScript. We have decided not to integrate the Dart VM into Chrome.
https://news.dartlang.org/2015/03/dart-for-entire-web.html
But I guess with the adoption of WebAssembly, that won't really matter anyway.
> In order to do what's best for our users and the web, and not just Google Chrome, we will focus our web efforts on compiling Dart to JavaScript. We have decided not to integrate the Dart VM into Chrome. https://news.dartlang.org/2015/03/dart-for-entire-web.html
But I guess with the adoption of WebAssembly, that won't really matter anyway.