I have landed several changes into dart-lang/sdk, which have each ultimately caused some bot somewhere to fail, as each change causes one or most customer tests to fail in the flutter/tests repo. There is no trybot for these "flutter customer tests."

This current feedback loop is very expensive for me and for the flutter engine rollers:

1. it takes several days for me to find out the change causes new failures in flutter/tests
2. it breaks some flutter auto-roller or other
3. breaking the auto-roller requires humans to identify the culprit, and revert my change
4. I must fix each customer's codebase to be compatible with my change
5. I must bump the commit SHA of each customer's codebase in flutter/tests
6. I land again, without any customer test trybots, cycling back to the top of this feedback loop.

CC @Hixie @jason-simmons @iskakaushik to perhaps fill in details I got wrong above