Jason Simmons 0ce96c8a55 Delete DartState during isolate shutdown
This solves two problems:
* UIDartState was being deleted during destruction of DartController after the
  isolate had been shut down.  The UIDartState held persistent handles to Dart
  objects, and deleting them when the isolate no longer exists caused an
  assertion failure.
* DartStates created for secondary isolates were never being deleted

Fixes https://github.com/flutter/flutter/issues/2549
2016-03-10 10:47:46 -08:00
..
2016-02-09 09:25:52 -08:00