Start by adding static castTo method to the interfaces. This provides everybody with the
desired implementation without exposing the classes.
When implementing the cast method, the recommended way is to (extend the base class,
but if you choose not to ...) use the castTo method.
If we ever get a language feature, we can implement the castTo method using that,
without being stuck with an unnecessary class.
Change-Id: I53274e60c88a4de519bead85d2ca44c1065a9c1a
Reviewed-on: https://dart-review.googlesource.com/26620
Commit-Queue: Lasse R.H. Nielsen <lrn@google.com>
Reviewed-by: Lasse R.H. Nielsen <lrn@google.com>
Reviewed-by: Leaf Petersen <leafp@google.com>
Lasse R.H. Nielsen