Update to current webrtc library

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

webrtc/rtc_base/event.h

@@ -0,0 +1,86 @@
+/*
+ *  Copyright 2004 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_EVENT_H_
+#define RTC_BASE_EVENT_H_
+
+#if defined(WEBRTC_WIN)
+#include <windows.h>
+#elif defined(WEBRTC_POSIX)
+#include <pthread.h>
+#else
+#error "Must define either WEBRTC_WIN or WEBRTC_POSIX."
+#endif
+
+namespace rtc {
+
+class Event {
+ public:
+  static const int kForever = -1;
+
+  Event();
+  Event(bool manual_reset, bool initially_signaled);
+  Event(const Event&) = delete;
+  Event& operator=(const Event&) = delete;
+  ~Event();
+
+  void Set();
+  void Reset();
+
+  // Waits for the event to become signaled, but logs a warning if it takes more
+  // than `warn_after_ms` milliseconds, and gives up completely if it takes more
+  // than `give_up_after_ms` milliseconds. (If `warn_after_ms >=
+  // give_up_after_ms`, no warning will be logged.) Either or both may be
+  // `kForever`, which means wait indefinitely.
+  //
+  // Returns true if the event was signaled, false if there was a timeout or
+  // some other error.
+  bool Wait(int give_up_after_ms, int warn_after_ms);
+
+  // Waits with the given timeout and a reasonable default warning timeout.
+  bool Wait(int give_up_after_ms) {
+    return Wait(give_up_after_ms,
+                give_up_after_ms == kForever ? 3000 : kForever);
+  }
+
+ private:
+#if defined(WEBRTC_WIN)
+  HANDLE event_handle_;
+#elif defined(WEBRTC_POSIX)
+  pthread_mutex_t event_mutex_;
+  pthread_cond_t event_cond_;
+  const bool is_manual_reset_;
+  bool event_status_;
+#endif
+};
+
+// These classes are provided for compatibility with Chromium.
+// The rtc::Event implementation is overriden inside of Chromium for the
+// purposes of detecting when threads are blocked that shouldn't be as well as
+// to use the more accurate event implementation that's there than is provided
+// by default on some platforms (e.g. Windows).
+// When building with standalone WebRTC, this class is a noop.
+// For further information, please see the
+// ScopedAllowBaseSyncPrimitives(ForTesting) classes in Chromium.
+class ScopedAllowBaseSyncPrimitives {
+ public:
+  ScopedAllowBaseSyncPrimitives() {}
+  ~ScopedAllowBaseSyncPrimitives() {}
+};
+
+class ScopedAllowBaseSyncPrimitivesForTesting {
+ public:
+  ScopedAllowBaseSyncPrimitivesForTesting() {}
+  ~ScopedAllowBaseSyncPrimitivesForTesting() {}
+};
+
+}  // namespace rtc
+
+#endif  // RTC_BASE_EVENT_H_