Merge from widevine repo of http:/go/wvgerrit/14707
This CL adds a check to oemcrypto_test to verify that when a
certificate is rewrapped, it does not show up in the clear. We can't
really verify that it is encrypted well, but we can check this.
bug: 21871738
Change-Id: I07c87c38a1e2a099a90a5be4e3350e91e09f6722