* feat: add support for WebUSB

* fixup for gn check

* fixup gn check on Windows

* Apply review feedback

Co-authored-by: Charles Kerr <charles@charleskerr.com>

* chore: address review feedback

* chore: removed unneeded code

* Migrate non-default ScopedObservation<> instantiations to ScopedObservationTraits<> in chrome/browser/

https://chromium-review.googlesource.com/c/chromium/src/+/4016595



Co-authored-by: Charles Kerr <charles@charleskerr.com>