Revert "Remove gBn/sConstructorMap."

This reverts commit c67f65df9a9832094df79c4f02dffa25ca2bb2b1.

Reason for revert: Break internal targets
Bug: 69122224
Bug: 70720496

Change-Id: I6373330871b504999653b4c0bad6bdd7111c25be
4 files changed