Make ObjectRegistry::InternalAdd GC safe

Because a call to IdentityHashCode may cause GC, the object pointer
may become invalid (if the object has been moved) on next uses. We
now access the object through a Handle to be GC safe.

Also remove unused methods.

Bug: 18098424
Change-Id: I38fb55c3a6be62c4d98d4c94272a9cfeba327598
2 files changed