feat(DI): Add a new lighter-weight "reflector" (just top-level methods).
feat(DI): Add a new lighter-weight "reflector" (just top-level methods).

Partial work towards https://github.com/dart-lang/angular/issues/532.

PiperOrigin-RevId: 164493843

matanlurey/angular,kevmoo/angular,matanlurey/angular,angulardart/angular,angulardart/angular,kevmoo/angular,matanlurey/angular,chalin/angular2,kevmoo/angular,chalin/angular2,chalin/angular2,angulardart/angular