When falling back to L3, release requests were failing. Information
requesting falling back to L3 is passed along when the session is opened.
Licenses however are released using the key set ID and information
requesting fallback to L3(CdmClientPropertySet) at that point is
unavailable. The release was actually attempting to release a license
at the default security level which is incorrect.
In addition, the mac keys were not being setup correctly and the release
message was signed with keys derived from the license request and not the
response. Both these issues have been addressed and unit tests added
to track release of offline licenses and usage reporting scenarios.
[ Merge of https://widevine-internal-review.googlesource.com/#/c/11062
from wv cdm repo ]
b/17073910
Change-Id: I5cd95a7dfe58ebae7ae27ece6c92e67755c1d665
9bc13a07a0