diff --git a/mozilla/js/src/jsapi.h b/mozilla/js/src/jsapi.h
index 5fafa15548e..17670d33f6a 100644
--- a/mozilla/js/src/jsapi.h
+++ b/mozilla/js/src/jsapi.h
@@ -1212,7 +1212,9 @@ struct JSExtendedClass {
     JSObjectOp          outerObject;
     JSObjectOp          innerObject;
     JSIteratorOp        iteratorObject;
-    JSObjectOp          wrappedObject;
+    JSObjectOp          wrappedObject;          /* NB: infallible, null
+                                                   returns are treated as
+                                                   the original object */
     void                (*reserved0)(void);
     void                (*reserved1)(void);
     void                (*reserved2)(void);
diff --git a/mozilla/js/src/jsinterp.c b/mozilla/js/src/jsinterp.c
index a6037466907..c71d67b1c4b 100644
--- a/mozilla/js/src/jsinterp.c
+++ b/mozilla/js/src/jsinterp.c
@@ -1522,13 +1522,19 @@ js_StrictlyEqual(JSContext *cx, jsval lval, jsval rval)
             robj = JSVAL_TO_OBJECT(rval);
             lclasp = OBJ_GET_CLASS(cx, lobj);
             rclasp = OBJ_GET_CLASS(cx, robj);
-            if (lclasp->flags & rclasp->flags & JSCLASS_IS_EXTENDED) {
-                JSExtendedClass *lxclasp = (JSExtendedClass *) lclasp,
-                                *rxclasp = (JSExtendedClass *) rclasp;
-                return (lxclasp->wrappedObject && rxclasp->wrappedObject)
-                       ? lxclasp->wrappedObject(cx, lval) ==
-                         rxclasp->wrappedObject(cx, rval)
-                       : lval == rval;
+            if (lclasp->flags & JSCLASS_IS_EXTENDED) {
+                JSExtendedClass *xclasp = (JSExtendedClass *) lclasp;
+                if (xclasp->wrappedObject &&
+                    (lobj = xclasp->wrappedObject(cx, lobj))) {
+                    lval = OBJECT_TO_JSVAL(lobj);
+                }
+            }
+            if (rclasp->flags & JSCLASS_IS_EXTENDED) {
+                JSExtendedClass *xclasp = (JSExtendedClass *) rclasp;
+                if (xclasp->wrappedObject &&
+                    (robj = xclasp->wrappedObject(cx, robj))) {
+                    rval = OBJECT_TO_JSVAL(robj);
+                }
             }
         }
         return lval == rval;
diff --git a/mozilla/js/src/xpconnect/src/XPCSafeJSObjectWrapper.cpp b/mozilla/js/src/xpconnect/src/XPCSafeJSObjectWrapper.cpp
index a55841dcdbf..6dc934d4e7e 100644
--- a/mozilla/js/src/xpconnect/src/XPCSafeJSObjectWrapper.cpp
+++ b/mozilla/js/src/xpconnect/src/XPCSafeJSObjectWrapper.cpp
@@ -201,6 +201,8 @@ JSExtendedClass sXPC_SJOW_JSClass = {
   },
   // JSExtendedClass initialization
   XPC_SJOW_Equality,
+  nsnull, // outerObject
+  nsnull, // innerObject
   nsnull, // iteratorObject
   XPC_SJOW_WrappedObject,
   JSCLASS_NO_RESERVED_MEMBERS