diff --git a/mozilla/xpfe/appshell/src/nsChromeTreeOwner.cpp b/mozilla/xpfe/appshell/src/nsChromeTreeOwner.cpp
index 48490edcc9f..0125bd7216e 100644
--- a/mozilla/xpfe/appshell/src/nsChromeTreeOwner.cpp
+++ b/mozilla/xpfe/appshell/src/nsChromeTreeOwner.cpp
@@ -63,6 +63,7 @@ NS_INTERFACE_MAP_BEGIN(nsChromeTreeOwner)
    NS_INTERFACE_MAP_ENTRY(nsIBaseWindow)
    NS_INTERFACE_MAP_ENTRY(nsIWebProgressListener)
    NS_INTERFACE_MAP_ENTRY(nsIInterfaceRequestor)
+   NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
 NS_INTERFACE_MAP_END
 
 //*****************************************************************************
diff --git a/mozilla/xpfe/appshell/src/nsChromeTreeOwner.h b/mozilla/xpfe/appshell/src/nsChromeTreeOwner.h
index f769d87add6..1d98ac08f4f 100644
--- a/mozilla/xpfe/appshell/src/nsChromeTreeOwner.h
+++ b/mozilla/xpfe/appshell/src/nsChromeTreeOwner.h
@@ -31,13 +31,15 @@
 #include "nsIDocShellTreeOwner.h"
 #include "nsIInterfaceRequestor.h"
 #include "nsIWebProgressListener.h"
+#include "nsWeakReference.h"
 
 class nsXULWindow;
 
 class nsChromeTreeOwner : public nsIDocShellTreeOwner,
                           public nsIBaseWindow, 
                           public nsIInterfaceRequestor,
-                          public nsIWebProgressListener
+                          public nsIWebProgressListener,
+                          public nsSupportsWeakReference
 {
 friend class nsXULWindow;
 
diff --git a/mozilla/xpfe/appshell/src/nsWebShellWindow.cpp b/mozilla/xpfe/appshell/src/nsWebShellWindow.cpp
index 4f1f7c87b81..2835a977e9e 100644
--- a/mozilla/xpfe/appshell/src/nsWebShellWindow.cpp
+++ b/mozilla/xpfe/appshell/src/nsWebShellWindow.cpp
@@ -233,10 +233,10 @@ NS_INTERFACE_MAP_BEGIN(nsWebShellWindow)
    NS_INTERFACE_MAP_ENTRY(nsIWebShellWindow)
    NS_INTERFACE_MAP_ENTRY(nsIWebShellContainer)
    NS_INTERFACE_MAP_ENTRY(nsIWebProgressListener)
-   NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
    NS_INTERFACE_MAP_ENTRY(nsIXULWindow)
    NS_INTERFACE_MAP_ENTRY(nsIBaseWindow)
    NS_INTERFACE_MAP_ENTRY(nsIInterfaceRequestor)
+   NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
 NS_INTERFACE_MAP_END
 
 nsresult nsWebShellWindow::Initialize(nsIXULWindow* aParent,