Oilpan: move WorkerGlobalScope to oilpan's heap.

This moves the WorkerGlobalScope object and the objects derived from it
to the Oilpan heap. This also includes the Console, Location and
Navigator interface objects that are attached to the worker global scope.

R=haraken@chromium.org,ager@chromium.org,abarth@chromium.org
BUG=340522

Review URL: https://codereview.chromium.org/178663004

git-svn-id: svn://svn.chromium.org/blink/trunk@168830 bbb929c8-8fbe-4397-9dbb-9b2b20218538