diff --git a/embedding/tests/mfcembed/components/PrintProgressDialog.h b/embedding/tests/mfcembed/components/PrintProgressDialog.h
index a65a7d8a8963..31db9edc0a86 100644
--- a/embedding/tests/mfcembed/components/PrintProgressDialog.h
+++ b/embedding/tests/mfcembed/components/PrintProgressDialog.h
@@ -12,6 +12,7 @@
 #include "nsIWebBrowserPrint.h"
 #include "nsIPrintSettings.h"
 #include "nsIPrintProgressParams.h"
+#include "nsCOMPtr.h"
 
 /////////////////////////////////////////////////////////////////////////////
 // CPrintProgressDialog dialog