Our toolchain fails to link unittests without this change.

Change-Id: I48cc61f45fe5d533ed207f987371893caf54a919
Reviewed-on: https://chromium-review.googlesource.com/c/1340293Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Ivica Bogosavljevic <ibogosavljevic@wavecomp.com>
Cr-Commit-Position: refs/heads/master@{#57634}