Update to current webrtc library

This is from the upstream library commit id
3326535126e435f1ba647885ce43a8f0f3d317eb, corresponding to Chromium
88.0.4290.1.

webrtc/rtc_base/gtest_prod_util.h

@@ -0,0 +1,38 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef RTC_BASE_GTEST_PROD_UTIL_H_
+#define RTC_BASE_GTEST_PROD_UTIL_H_
+
+// Define our own version of FRIEND_TEST here rather than including
+// gtest_prod.h to avoid depending on any part of GTest in production code.
+#define FRIEND_TEST_WEBRTC(test_case_name, test_name) \
+  friend class test_case_name##_##test_name##_Test
+
+// This file is a plain copy of Chromium's base/gtest_prod_util.h.
+//
+// This is a wrapper for gtest's FRIEND_TEST macro that friends
+// test with all possible prefixes. This is very helpful when changing the test
+// prefix, because the friend declarations don't need to be updated.
+//
+// Example usage:
+//
+// class MyClass {
+//  private:
+//   void MyMethod();
+//   FRIEND_TEST_ALL_PREFIXES(MyClassTest, MyMethod);
+// };
+#define FRIEND_TEST_ALL_PREFIXES(test_case_name, test_name) \
+  FRIEND_TEST_WEBRTC(test_case_name, test_name);            \
+  FRIEND_TEST_WEBRTC(test_case_name, DISABLED_##test_name); \
+  FRIEND_TEST_WEBRTC(test_case_name, FLAKY_##test_name);    \
+  FRIEND_TEST_WEBRTC(test_case_name, FAILS_##test_name)
+
+#endif  // RTC_BASE_GTEST_PROD_UTIL_H_