diff --git a/layout/generic/nsIFrame.h b/layout/generic/nsIFrame.h
index 8f34fab12bc..65d84ea1594 100644
--- a/layout/generic/nsIFrame.h
+++ b/layout/generic/nsIFrame.h
@@ -34,6 +34,7 @@
 #include "nsITheme.h"
 #include "nsLayoutUtils.h"
 #include "nsQueryFrame.h"
+#include "nsStringGlue.h"
 #include "nsStyleContext.h"
 #include "nsStyleStruct.h"
 
@@ -3225,6 +3226,11 @@ public:
     fputs(t.get(), out);
   }
   void ListTag(nsACString& aTo) const;
+  nsAutoCString ListTag() const {
+    nsAutoCString tag;
+    ListTag(tag);
+    return tag;
+  }
   static void ListTag(nsACString& aTo, const nsIFrame* aFrame);
   void ListGeneric(nsACString& aTo, const char* aPrefix = "", uint32_t aFlags = 0) const;
   enum {