b878294e06
This is a re-land of https://dart-review.googlesource.com/c/sdk/+/247601 with some additional changes to allow for certain null uris in some previously migrated package:front_end code. Note that nulls were flowing through these apis already, this just acknowledges that fact :). Bug: https://github.com/dart-lang/sdk/issues/49212 Change-Id: I4528bfdec1bc9114715afd3fea06d1249054d2a2 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/247765 Commit-Queue: Jake Macdonald <jakemac@google.com> Auto-Submit: Jake Macdonald <jakemac@google.com> Reviewed-by: Johnni Winther <johnniwinther@google.com>