More OEMCrypto Usage Table Unit Tests

Merge from widevine repo of http://go/wvgerrit/23421

This CL adds some more unit tests for big usage tables, and corrects a
problem found in the reference code.

Change-Id: Iae9a4406d79a13362223c2b4da7365b845d92382

libwvdrmengine/oemcrypto/mock/src/oemcrypto_mock.cpp

@@ -948,7 +948,6 @@ extern "C" OEMCryptoResult OEMCrypto_RewrapDeviceRSAKey30(
     LOGE("[_RewrapDeviceRSAKey30(): RAND_bytes failed.");
     return OEMCrypto_ERROR_UNKNOWN_FAILURE;
   }
-  // TODO(fredgc): Don't use the keybox to encrypt the wrapped RSA key.
   const std::vector<uint8_t> context(
       wrapped->context, wrapped->context + sizeof(wrapped->context));
   // Generate mac and encryption keys for encrypting the signature.
@@ -1157,7 +1156,6 @@ extern "C" OEMCryptoResult OEMCrypto_LoadDeviceRSAKey(
       dump_hex("iv", wrapped->iv, sizeof(wrapped->iv));
     }
   }
-  // TODO(fredgc): Don't use the keybox to encrypt the wrapped RSA key.
   if (!crypto_engine->ValidRootOfTrust()) {
     LOGE("[OEMCrypto_LoadDeviceRSAKey(): ERROR_KEYBOX_INVALID]");
     return OEMCrypto_ERROR_KEYBOX_INVALID;