GitLab

Run git cl format over BUILD.gn, and add a line space here and there to
increase readability.

Tbr: cavalcanti@chromium.org
Bug: None
Change-Id: Id46ff314c0fe820880fd441858cbaca6d7754b46
Reviewed-on: https://chromium-review.googlesource.com/912209Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#536036}