d76ae6dbcb
--timeline-streams has been listed in the "options implied by --observe" section of the dart run help messages, but it has been getting ignored. This CL fixes that problem. TEST=manual testing, CI Change-Id: Ib6c2425a2681b61375df186673e0f195e3fae580 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/288581 Reviewed-by: Ben Konyi <bkonyi@google.com>