ae41760d93
Work towards https://github.com/dart-lang/sdk/issues/61597 * DiagnosticsTreeStyle is used just below in DiagnosticsProperty. * BoxConstraints is used in the `flutter_completion_benchmark`. * Constraints is the superclass of BoxConstraints. * The vector_math export is so that a few tests have access to the Matrix4 class. * FutureBuilder and StreamBuilder are needed for the flutter_wrap_builder correction producer. All of these changes bring the mocks/stubs closer to the real sources (none are a divergence). Change-Id: I80d746db3372417d7125aa1f3c2b0604a143f43b Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/476144 Reviewed-by: Brian Wilkerson <brianwilkerson@google.com> Commit-Queue: Samuel Rawlins <srawlins@google.com>