Today, Dart team member Kasper Lund notified us of a breaking change. The #resource directive is being removed from the spec and implementations. From the email:
We've decided to remove support for the #resource directive and
instead rely on metadata annotations for associating external
resources with Dart programs. I've submitted a change that removes the
support for #resource from dart2js in r11489 and the other
implementations (the VM and the analyzer) will also stop supporting
the tag in the near future.
Now is the time to remove any uses of #resource. Please drop by the mailing list if you have any questions. Thanks for trying Dart!