Oilpan build fix for r174893 and r174900.

TBR=oilpan-reviews@chromium.org,dcheng@chromium.org,ericwilligers@chromium.org
BUG=

Review URL: https://codereview.chromium.org/303673005

git-svn-id: svn://svn.chromium.org/blink/trunk@174913 bbb929c8-8fbe-4397-9dbb-9b2b20218538