Temporarily re-add methods and classes removed in ag/1420175.

The methods and classes are hidden and marked with @UnsupportedAppUsage.
This fixes broken dogfooders while the new SDK is being propagated.

Bug: 181887768
Test: Jetpack unit tests against old SDK
Change-Id: Ibc8aaed6ffa751b75bf5b23e04547eba2a4cda86