GitLab

The concept is only well-defined on Linux, but the measurement was only
implemented and used on Windows.

Bug: 819289
Change-Id: Ie69e550019e29b473c8efcae8f3c8bbc390e737b
Reviewed-on: https://chromium-review.googlesource.com/956575Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Primiano Tucci <primiano@chromium.org>
Commit-Queue: Erik Chen <erikchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543435}