7906ccf7ea
Reverses https://dart-review.googlesource.com/c/sdk/+/269141. Now that the pubspec specifies 2.19 as the minimum version, we can swap to IndexError.check instead of checkValidIndex. Change-Id: I0dab64b4c8408a29b8bea35920e3f5e69e6e92d9 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/294124 Commit-Queue: Kallen Tu <kallentu@google.com> Reviewed-by: Paul Berry <paulberry@google.com>