1 files changed, 36 insertions, 0 deletions
diff --git a/third_party/libwebrtc/rtc_base/containers/identity.h b/third_party/libwebrtc/rtc_base/containers/identity.h
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--- /dev/null
+++ b/third_party/libwebrtc/rtc_base/containers/identity.h
@@ -0,0 +1,36 @@
+/*
+ *  Copyright (c) 2021 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.
+ */
+
+// This implementation is borrowed from Chromium.
+
+#ifndef RTC_BASE_CONTAINERS_IDENTITY_H_
+#define RTC_BASE_CONTAINERS_IDENTITY_H_
+
+#include <utility>
+
+namespace webrtc {
+
+// Implementation of C++20's std::identity.
+//
+// Reference:
+// - https://en.cppreference.com/w/cpp/utility/functional/identity
+// - https://wg21.link/func.identity
+struct identity {
+  template <typename T>
+  constexpr T&& operator()(T&& t) const noexcept {
+    return std::forward<T>(t);
+  }
+
+  using is_transparent = void;
+};
+
+}  // namespace webrtc
+
+#endif  // RTC_BASE_CONTAINERS_IDENTITY_H_