9c8749db96
Flag for 'base', 'final', 'interface' and mixin classes. Change-Id: I51037678826527a36b6dae731f43c8f36fead215 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/276765 Commit-Queue: Kallen Tu <kallentu@google.com> Reviewed-by: Nate Bosch <nbosch@google.com> Reviewed-by: Brian Wilkerson <brianwilkerson@google.com> Reviewed-by: Johnni Winther <johnniwinther@google.com>