Copied OEMCrypto utils to Android.

The OEMCrypto utils have been copied over from the CDM repo.
Tests have been excluded for this CL.

Files represent a snapshot taken from http://go/wvgerrit/148270
and http://go/wvgerrit/148372.

Bug: 205902021
Change-Id: I1a58952cd1436a48974367c5436bf7296163e6f1

libwvdrmengine/oemcrypto/util/include/oemcrypto_key_deriver.h

@@ -0,0 +1,61 @@
+// Copyright 2021 Google LLC. All Rights Reserved. This file and proprietary
+// source code may only be used and distributed under the Widevine License
+// Agreement.
+//
+//  Reference implementation utilities of OEMCrypto APIs
+//
+#ifndef WVOEC_UTIL_KEY_DERIVER_H_
+#define WVOEC_UTIL_KEY_DERIVER_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <memory>
+#include <vector>
+
+#include "cmac.h"
+
+namespace wvoec {
+namespace util {
+class KeyDeriver {
+ public:
+  // Create a new key deriver using either the session key or the device
+  // key.
+  // Returns an empty pointer if the key size is not valid.
+  static std::unique_ptr<KeyDeriver> Create(const uint8_t* key,
+                                            size_t key_size);
+  static std::unique_ptr<KeyDeriver> Create(const std::vector<uint8_t>& key);
+
+  // Derive the mac_key[server] from the provided |mac_key_context|.
+  bool DeriveServerMacKey(const uint8_t* mac_key_context,
+                          size_t mac_key_context_size,
+                          std::vector<uint8_t>* mac_key_server);
+  bool DeriveServerMacKey(const std::vector<uint8_t>& mac_key_context,
+                          std::vector<uint8_t>* mac_key_server);
+
+  // Derive the mac_key[client] from the provided |mac_key_context|.
+  bool DeriveClientMacKey(const uint8_t* mac_key_context,
+                          size_t mac_key_context_size,
+                          std::vector<uint8_t>* mac_key_client);
+  bool DeriveClientMacKey(const std::vector<uint8_t>& mac_key_context,
+                          std::vector<uint8_t>* mac_key_client);
+
+  // Derive the enc_key from the provided |enc_key_context|.
+  bool DeriveEncryptionKey(const uint8_t* enc_key_context,
+                           size_t enc_key_context_size,
+                           std::vector<uint8_t>* enc_key);
+  bool DeriveEncryptionKey(const std::vector<uint8_t>& enc_key_context,
+                           std::vector<uint8_t>* enc_key);
+
+  ~KeyDeriver() {}
+
+ private:
+  KeyDeriver() {}
+
+  bool Init(const uint8_t* key, size_t key_size);
+
+  std::unique_ptr<Cmac> cmac_;
+};
+}  // namespace util
+}  // namespace wvoec
+#endif  // WVOEC_UTIL_KEY_DERIVER_H_