diff --git a/layout/base/nsChangeHint.h b/layout/base/nsChangeHint.h
index 55d90f2d8692..14b7fc7a4b22 100644
--- a/layout/base/nsChangeHint.h
+++ b/layout/base/nsChangeHint.h
@@ -12,7 +12,7 @@
 #include "nsDebug.h"
 #include "nsTArray.h"
 
-class nsCSSSelector;
+struct nsCSSSelector;
 
 // Defines for various style related constants