Oilpan: speculative build fix for ScreenOrientationDispatcher

Oilpan builds broken by r173084 - just giving this a whirl to green
those bots.

TBR=haraken@chromium.org,zerny@chromium.org

Review URL: https://codereview.chromium.org/266633008

git-svn-id: svn://svn.chromium.org/blink/trunk@173090 bbb929c8-8fbe-4397-9dbb-9b2b20218538