1fb5352943
Also makes option handling more agnostic to default and negatable values, and disallows trying to use the preview server outside of upgrade. Change-Id: Icff10bd016d822edc9c37c0069ebc0c851f78a7e Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/128920 Reviewed-by: Brian Wilkerson <brianwilkerson@google.com> Auto-Submit: Janice Collins <jcollins@google.com> Commit-Queue: Janice Collins <jcollins@google.com>