(This is a merge of http://go/wvgerrit/150131 to the Android repo.)
This patch changes the code path in the CDM so that the first-stage
provisioning request for Provisioning 4.0 is always encrypted with the
Widevine service certificate instead of the client-set service
certificate, reflecting that the first-stage provisioning is always
handled by Widevine.
This patch also makes several methods on the ServiceCertificate class
const. This has no impact on their behavior.
Bug: 221443151
Test: prov40 tests
Change-Id: Ide4c3927afadcd45ae7fb629b99e2f55cc29d56e