Oilpan: fix build after r175264.

Finalization of ScreenOrientationController now needed, adjust GC class.

R=haraken@chromium.org,ager@chromium.org
BUG=162827
NOTRY=true

Review URL: https://codereview.chromium.org/305363003

git-svn-id: svn://svn.chromium.org/blink/trunk@175274 bbb929c8-8fbe-4397-9dbb-9b2b20218538