b5e7966dee
The utility class DartTypeComparator allows to compare two dart types under various assumptions, such as ignoring nullability at the top-level type node or equating all top types. Change-Id: I998e4a0a3ac236077cd1bcd12a5ad146ff10bb1d Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/149427 Commit-Queue: Dmitry Stefantsov <dmitryas@google.com> Reviewed-by: Johnni Winther <johnniwinther@google.com>