This change creates a unique id in the cdm identifier in order to force
a one-to-one mapping between WVDrmPlugin instances and CDM Engines. This
change simplifies some assumptions. This includes ensuring that the
metrics for a given MediaDrm instance map to a given CdmEngine instance.
This change contains the original change go/ag/3819203 and a fix to the
deadlock that was seen on Marlin and Taimen.
Bug: 73724453
Test: Updated unit tests. GTS test pass. Shaka Player, Netflix and Google Play test.
Change-Id: Ib208204a1b794df9f306fa11d13a8bb6cd6889f7