The engine is a necessarily complicated product and can be difficult to work in for contributors that do not frequently live in the engine code. Personally I have to open a wiki page or two every time I want to jump in the engine code.

This umbrella issue is to track all work related to building out the feature request for a mono tool designed for contributor and CI to use.

The tool should be:

1. Written in dart
   • Maximize number of contributors that have high proficiency
   • Runs on every platform we support
2. Live in the engine repo `script/tool/bin/engine.dart
   • Allows for single repo change
   • Easier to keep up to date
   • Code reviewable
3. Can build all targets dart run engine.dart build --all
   • At 6 platforms this can be annoying to figure out
4. Can lint all targets dart run engine.dart lint --all
5. Can run all unit/(integration?) tests
   • Building is hard enough, understanding how to run all tests few humans know how to do
6. Used by CI in pre submit
   • Ensures build/lint/test continues to work because if they fail presubmit fails
   • Gives contributors with domain expertise the ability to enforce or exempt code as it makes sense for their area of expertise
7. The tool itself has unit tests
   • This lets tool contributors and reviewers be more confident in changes
   • The tool unit tests are run as part of presubmit

This is not a new concept for the Dash Team. Flutter tool offers a public implementation of something similar and the packages repo has a contributor focused version of the same principals. This feature request is asking we apply the same idea to engine.