Needed to work on Chrome OS.

BUG=angleproject:1297

Change-Id: I78e18472780745f73257c8954f263d236ff92180
Reviewed-on: https://chromium-review.googlesource.com/323470
Tryjob-Request: Frank Henigman <fjhenigman@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Frank Henigman <fjhenigman@chromium.org>