It triggered an include guard warning on Windows Clang

This reverts commit 6f6c5580.

Change-Id: Ibd4f2851f311a494f16376d8eed38f3119594761
Reviewed-on: https://chromium-review.googlesource.com/338933Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>