There were several enum types that all were used for key systems. This
combines them into one to make it more clear and only needing to update
one. This also uses a bit field to specify multiple key systems instead
of using a std::vector.
Change-Id: Ia88039835492a5bd47f449ba4b76187046deeec0
Add crypto_period_seconds to Widevine key request
When using key rotation with Widevine DRM, a key server has to know
the duration of crypto period to relate generated keys to the media
playback time. This helps the server to provide relevant keys to
a client during license request.
Closes#544.
Jacob Trimble
srebrnyp
KongQun Yang
Haoming Chen