Merge from Widevine repo of http://go/wvgerrit/93404
This is the unit tests, reference code, and documentation for
OEMCrypto v16.2. Backwards compatibility should work for a v15
OEMCrypto.
Some review comments will be addressed in future CLs.
Bug: 141247171
Test: Unit tests
Test: Media GTS tests on bonito
Change-Id: I9d427c07580e180c0a4cfdc4a68f538d351c0ddd
db2050dff1