Merge changes I01b45c86,I10307aea,Iefccd6ff,Ibbda8e9a,I71a7f59b

* changes:
  ART: Remove more object_callbacks.h includes
  ART: Replace or remove some ObjectCallback Walk functions
  ART: Remove old visit functions
  ART: Use VisitObjects visitor functions
  ART: Add templated VisitObjects