Merge from Widevine repo if http://go/wvgerrit/13781
This CL adds several unit tests that are specifically designed to test
features that are required for Android CDM but not other platforms.
Once this CL has been merged, future CLs will modify the main
oemcrypto test file so that some tests are skipped if their features
are not implemented.
Change-Id: I55b8cbb9c13d2db88bd4f56bba31a4aab3306067