The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0ea8c7e4c2540865661f8420966dc5b7ea4d34cf

commit 0ea8c7e4c2540865661f8420966dc5b7ea4d34cf
Author: Roberto Carrillo <robertocn@google.com>
Date: Fri Jun 09 21:30:20 2017

[Findit] Separate parsing OWNERS file tags and component mapping generation.

This is the first patch to implement the generated file detailed in
https://docs.google.com/document/d/1TGmugh1RGsQpHwkWA6Yo-J0_F_0vxgMjk06uDSZ5u0s/edit#heading=h.s59ky3bav81t

It separates the logic that traverses the tree and parses OWNERS files,
from the part that aggregates and validates such data.

It also adds support for the `# OS:` tag.

R=sergiyb@chromium.org,katesonia@chromium.org,stgao@chromium.org
BUG=728002

Change-Id: I930f3c32d0185165c3d6b1908b2997eed09f4e56
Reviewed-on: https://chromium-review.googlesource.com/518449
Commit-Queue: Roberto Carrillo <robertocn@chromium.org>
Reviewed-by: Sergiy Byelozyorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#478424}
[modify] https://crrev.com/0ea8c7e4c2540865661f8420966dc5b7ea4d34cf/tools/checkteamtags/checkteamtags.py
[modify] https://crrev.com/0ea8c7e4c2540865661f8420966dc5b7ea4d34cf/tools/checkteamtags/extract_components.py
[modify] https://crrev.com/0ea8c7e4c2540865661f8420966dc5b7ea4d34cf/tools/checkteamtags/extract_components_test.py
[modify] https://crrev.com/0ea8c7e4c2540865661f8420966dc5b7ea4d34cf/tools/checkteamtags/owners_file_tags.py
[add] https://crrev.com/0ea8c7e4c2540865661f8420966dc5b7ea4d34cf/tools/checkteamtags/owners_file_tags_test.py