Oilpan: Move GeolocationController back to off-heap

r175404 broke oilpan builds, because r175404 switched GeolocationController from being a Page (which is on-heap) supplement to a LocalFrame (which is not yet on-heap) supplement.

As a quick fix, this CL moves GeolocationController back to off-heap.

BUG=340522

Review URL: https://codereview.chromium.org/314873002

git-svn-id: svn://svn.chromium.org/blink/trunk@175430 bbb929c8-8fbe-4397-9dbb-9b2b20218538