Previously, to associate a MediaDrm session with MediaCrypto,
the MediaDrm sessionId was passed as initData to the MediaCrypto
constructor. This is not ideal for two reasons: it's pretty
obscure and you can't change the association without tearing
down the MediaCodec/MediaCrypto and starting all over. Use
cases like key rotation require being able to update the
MediaDrm session post-construction. This CL addresses both of
these issues.
bug: 19570317
Change-Id: Iede35e73e9007df13254edaa5877cb4832b28646
