a49dce0631
It didn't wind up being used, and its presence limits our ability to modify the graph propagation algorithm (which I plan to do in a follow-up CL). Change-Id: I48a9b879f25295075e8d95eb3fb0185839303957 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/133425 Reviewed-by: Mike Fairhurst <mfairhurst@google.com>