diff --git a/widget/src/mac/nsMacMessagePump.h b/widget/src/mac/nsMacMessagePump.h
index f8787c15d6a7..2f7405d166c9 100644
--- a/widget/src/mac/nsMacMessagePump.h
+++ b/widget/src/mac/nsMacMessagePump.h
@@ -39,6 +39,7 @@
 
 class nsToolkit;
 class nsMacMessageSink;
+struct PLEventQueue;
 
 //================================================
 
@@ -52,6 +53,7 @@ private:
 	PRBool					mInBackground;
 	nsToolkit*				mToolkit;
 	nsMacMessageSink*       mMessageSink;
+	PLEventQueue*			mEventQueue;
 
 	// CLASS METHODS