diff --git a/rtc_base/event.h b/rtc_base/event.h
index 2e11002..3f5f8b3 100644
--- a/rtc_base/event.h
+++ b/rtc_base/event.h
@@ -49,20 +49,26 @@
 #endif
 };
 
-// This class is provided for compatibility with Chromium.
+// 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 class
-// in Chromium.
+// 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_