- [x] Introduce DependencyChecker which can determine if any dependencies have been modified.
- [x] Move the DartDependencyBuilder into a separate file.
- [x] Add unit tests for DartDependencyBuilder.
- [x] Add unit tets for DependencyChecker
Part of #7014
This moves all of the various .analysis_options* files to the flutter repo root so that it's easier to
* remember to keep them all in sync, and
* easily refer customers to them