GitLab

Reference:
https://gn.googlesource.com/gn/+/master/docs/reference.md#var_public_deps

Allow inheriting ability to include public headers.

Test: CQ
Bug: 1121813
Change-Id: I9e8111319be6fbe33eb11bfd58807e0e89bf84c2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2376380
Commit-Queue: Linkun Chen <lkchen@chromium.org>
Reviewed-by: Mirko Bonadei <mbonadei@chromium.org>
Cr-Commit-Position: refs/heads/master@{#801705}