Backport Chromium changes: revision 251981

https://src.chromium.org/viewvc/chrome?revision=251981&view=revision

Hide X11 dependencies when use_x11=0.

When using a non X11 build with Ozone, we still have dependencies on
X11. This patch tries to hide X11 and related dependencies when
use_x11=0

Review URL: https://codereview.chromium.org/148643002

Signed-off-by: Baptiste DURAND <baptiste.durand@open.eurogiciel.org>