diff --git a/rtc_base/event.h b/rtc_base/event.h
index ce2666fb3f..7e61c4c8a6 100644
--- a/rtc_base/event.h
+++ b/rtc_base/event.h
@@ -49,6 +49,20 @@ class Event {
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(Event);
 };
 
+// This class is 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 class
+// in Chromium.
+class ScopedAllowBaseSyncPrimitives {
+ public:
+  ScopedAllowBaseSyncPrimitives() {}
+  ~ScopedAllowBaseSyncPrimitives() {}
+};
+
 }  // namespace rtc
 
 #endif  // RTC_BASE_EVENT_H_