This is a combined merge of several small changes to the core in the
Widevine CDM repository:
http://go/wvgerrit/10941
Rename privacy_crypto to allow more variants.
http://go/wvgerrit/11530
Add Missing Header to properties.h
http://go/wvgerrit/11531
More Loosely Couple CdmEngine and CdmSession
Change-Id: I5b3f738ae495ab267da1440421dd7aa6f7860194