Clean up "Deprecated at Birth" APIs.

When APIs are refactored mid-release, they can often be left marked
as @Deprecated with the intention of eventually removing them before
the SDK is finalized.

Well, the time has come to finalize the SDK, so let's clean them up.

Bug: 189325658
Test: manual
Change-Id: I48e3e1c1306fbaf071e4acfd9e8107e6ad564ffe