Relevance of @MirrorsUsed, Smoke annotation when using reflection in Dartium

I have fairly significant application written with Dart and Polymer which uses reflection in a factory method and runs fairly well in Dartium. The factory generates subclass instances using the subclass name passed to it as a parameter.

I'm fine with never generating Javascript and forcing my users, if any, to use Dartium. I'm also fine with modifying any @MirrorsUsed annotations when the list of instantiable subclasses changes. The page at http://ift.tt/2lZjS8N seems to imply that performance and/or codesize can be greatly improved, even in Dartium, by the use of Smoke.

How much does Dartium, or the Dart analyzer, do when running a Dart app? Will Smoke, or even just @MirrorsUsed annotations, do anything for an app in Dartium?