Fix Oilpan build after r182048.

BUG=
R=loislo@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/573953004

git-svn-id: svn://svn.chromium.org/blink/trunk@182051 bbb929c8-8fbe-4397-9dbb-9b2b20218538