GitLab

- Updates relevant chromeos BUILD.gn files
- Add imports and exports to os_route, os_settings_route and
  os_settings.js
- Update bluetooth test files.

Bug: 1045266
Change-Id: I81e52893befe36b4757283428b7844b2de8fe514
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2220218
Commit-Queue: Nnamdi Theodore Johnson-kanu <tjohnsonkanu@google.com>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Reviewed-by: Regan Hsu <hsuregan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#779949}