1 files changed, 59 insertions, 0 deletions
diff --git a/third_party/libwebrtc/api/field_trials.h b/third_party/libwebrtc/api/field_trials.h
new file mode 100644
index 0000000000..bf7a7cc625
--- /dev/null
+++ b/third_party/libwebrtc/api/field_trials.h
@@ -0,0 +1,59 @@
+/*
+ *  Copyright (c) 2022 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 API_FIELD_TRIALS_H_
+#define API_FIELD_TRIALS_H_
+
+#include <memory>
+#include <string>
+
+#include "absl/strings/string_view.h"
+#include "api/field_trials_registry.h"
+#include "rtc_base/containers/flat_map.h"
+
+namespace webrtc {
+
+// The FieldTrials class is used to inject field trials into webrtc.
+//
+// Field trials allow webrtc clients (such as Chromium) to turn on feature code
+// in binaries out in the field and gather information with that.
+//
+// They are designed to be easy to use with Chromium field trials and to speed
+// up developers by reducing the need to wire up APIs to control whether a
+// feature is on/off.
+//
+// The field trials are injected into objects that use them at creation time.
+//
+// NOTE: Creating multiple FieldTrials-object is currently prohibited
+// until we remove the global string (TODO(bugs.webrtc.org/10335))
+// (unless using CreateNoGlobal):
+class FieldTrials : public FieldTrialsRegistry {
+ public:
+  explicit FieldTrials(const std::string& s);
+  ~FieldTrials();
+
+  // Create a FieldTrials object that is not reading/writing from
+  // global variable (i.e can not be used for all parts of webrtc).
+  static std::unique_ptr<FieldTrials> CreateNoGlobal(const std::string& s);
+
+ private:
+  explicit FieldTrials(const std::string& s, bool);
+
+  std::string GetValue(absl::string_view key) const override;
+
+  const bool uses_global_;
+  const std::string field_trial_string_;
+  const char* const previous_field_trial_string_;
+  const flat_map<std::string, std::string> key_value_map_;
+};
+
+}  // namespace webrtc
+
+#endif  // API_FIELD_TRIALS_H_