In order to migrate the migration tool to null safety, it can't have a
dependency on `package:dartdev`, because `package:dartdev` isn't
migrated yet. (This is a problem because once the migration tool's
tests have been migrated to null safety, they will require the
transitive closure of all the packages they depend on to also be
migrated).
Fortunately, it's quite easy to change the migration tool so that it
doesn't depend on `package:dartdev`; we only need to move the class
`MigrateCommand` from `package:nnbd_migration` to `package:dartdev`.
To make this work, we have to move the constant `migrationGuideLink`
from `MigrateCommand` to `MigrationCli`, and make the method
`MigrationCli._defineOptions` public.
Change-Id: Ie1ce8db0e8245e98bbb72facddd723300816340e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/204540
Reviewed-by: Devon Carew <devoncarew@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>
Paul Berry
c041afad9f