656584e8b6
It seems this was introduced internally only in cl/220297783 but never ported externally Change-Id: Ibcc35b091a32b422b86b7eea36b52165b11987d3 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/205625 Reviewed-by: Sigmund Cherem <sigmund@google.com> Commit-Queue: Mark Zhou <markzipan@google.com>