Add implementation of getInterfaceHash()

Exempt-From-Owner-Approval: cherry-pick from internal
Bug: 136065010
Test: m
Change-Id: I314f19aeca82cc8653eab71c9526ea7a208e6b50
Merged-In: I314f19aeca82cc8653eab71c9526ea7a208e6b50
8 files changed