Pick widevine oemcrypto-v18 change

No-Typo-Check: From a third party header file
Bug: 260918793
Test: unit tests
Test: atp v2/widevine-eng/drm_compliance
Change-Id: I36effd6a10a99bdb2399ab1f4a0fad026d607c70

libwvdrmengine/oemcrypto/util/include/oemcrypto_key_handle.h

@@ -0,0 +1,63 @@
+// Copyright 2022 Google LLC. All Rights Reserved. This file and proprietary
+// source code may only be used and distributed under the Widevine License
+// Agreement.
+//
+// Implements utility functions for serializing and deserializing the fake key
+// handles used by the Ref and Testbed.
+//
+#ifndef WVOEC_UTIL_KEY_HANDLE_H_
+#define WVOEC_UTIL_KEY_HANDLE_H_
+
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "OEMCryptoCENC.h"
+#include "log.h"
+
+namespace wvoec {
+namespace util {
+// Size of a key handle, which for this implementation is just a session ID.
+constexpr size_t kKeyHandleSize = sizeof(OEMCrypto_SESSION);
+
+OEMCryptoResult SerializeSessionToKeyHandle(OEMCrypto_SESSION session,
+                                            uint8_t* key_handle,
+                                            size_t* key_handle_length) {
+  if (key_handle_length == nullptr) {
+    LOGE("Null key handle length");
+    return OEMCrypto_ERROR_INVALID_CONTEXT;
+  }
+
+  if (key_handle == nullptr || *key_handle_length < kKeyHandleSize) {
+    *key_handle_length = kKeyHandleSize;
+    return OEMCrypto_ERROR_SHORT_BUFFER;
+  }
+
+  *key_handle_length = kKeyHandleSize;
+  memcpy(key_handle, &session, kKeyHandleSize);
+  return OEMCrypto_SUCCESS;
+}
+
+OEMCryptoResult DeserializeKeyHandleToSession(const uint8_t* key_handle,
+                                              size_t key_handle_length,
+                                              OEMCrypto_SESSION* session) {
+  if (key_handle == nullptr) {
+    LOGE("Null key handle");
+    return OEMCrypto_ERROR_INVALID_CONTEXT;
+  }
+  if (session == nullptr) {
+    LOGE("Null session");
+    return OEMCrypto_ERROR_INVALID_CONTEXT;
+  }
+
+  if (key_handle_length != kKeyHandleSize) {
+    LOGE("Invalid key handle length");
+    return OEMCrypto_ERROR_INVALID_CONTEXT;
+  }
+
+  memcpy(session, key_handle, kKeyHandleSize);
+  return OEMCrypto_SUCCESS;
+}
+}  // namespace util
+}  // namespace wvoec
+#endif  // WVOEC_UTIL_KEY_HANDLE_H_