c7123c96cd
This is part 5 of a broken down version of the #140101 refactor. This PR removes direct use of `print` and replaces it with a callback.
The files in this directory are used as part of the tests in the
flutter_tools package. Some are here because here these tests need a
pubspec.yaml that references the flutter framework (which is
intentionally not true of the flutter_tools package). Others are
here mostly out of peer pressure.