Merge from master branch of Widevine repo of http://go/wvgerrit/66069
Merge from oemcrypto-v15 branch of Widevine repo of http://go/wvgerrit/62420
This is the full API -- not just the delta.
Bug: 111939411
Test: docs only
Test: tested as part of http://go/ag/5501993
Change-Id: Id839bf10666e271c882fc437f9ebbd3941d23784