This finally allows to include the factory.h header without having to
also inlcude the object-inl.h inline header. It will in turn enable the
removal of the last inline header inclusion violation.

R=marja@chromium.org

Change-Id: Ice2821e1f74cf428d80c8ebf606a218026f37677
Reviewed-on: https://chromium-review.googlesource.com/654862Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47880}