Previously, each top level key/value pair in the file represented a
feature, so in order to make room for the new field, these were all
moved under a "features:" header.
Code generators have been updated to produce the same result as they
did before; in future CLs I'll update them to generate code based on
the new field.
Change-Id: Ia2266dd0d92796f15460127742eb2b56f64438e6
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/138101
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Paul Berry
d0826bdbd5