OEMCrypto Tests Provisioning Method

Merge from widevine repo of http://go/wvgerrit/21682

This CL updates oemcrypto/test/oec_device_features.cpp to figure out
the provisioning method and filter out tests that are not relevant to
the device's method.

This CL also introduces unit tests for GetOEMPublicCertificate.

Unit tests for RewrapDeviceRSAKey30 will be in a future CL.

Change-Id: Ib7065ce866d1171ca61b9aa08188fa2ac8d90fc2

libwvdrmengine/oemcrypto/test/oec_session_util.h

@@ -203,6 +203,9 @@ class Session {
   void TestDecryptCTR(bool select_key_first = true,
                       OEMCryptoResult expected_result = OEMCrypto_SUCCESS,
                       int key_index = 0);
+  // Calls OEMCrypto_GetOEMPublicCertificate and loads the OEM cert's public
+  // rsa key into public_rsa_.
+  void LoadOEMCert(bool verify_cert = false);
   // Creates RSAPrivateKeyMessage for the specified rsa_key, encrypts it with
   // the specified encryption key, and then signs it with the server's mac key.
   // If encryption_key is null, use the session's enc_key_.