Fixing bug 106181. When a window object is asked for the numeric property n, we return the n:th frame in the window, but if there is no n:th frame we should let the JS engine do its thing w/o forsing it to return null. r=jag@netscape.com, sr=rpotts@netscape.com

dom/src/base/nsDOMClassInfo.cpp

@@ -2365,8 +2365,10 @@ nsWindowSH::GetProperty(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
 
       frames->Item(JSVAL_TO_INT(id), getter_AddRefs(f));
 
-      rv = WrapNative(cx, ::JS_GetGlobalObject(cx), f,
-                      NS_GET_IID(nsIDOMWindow), vp);
+      if (f) {
+        rv = WrapNative(cx, ::JS_GetGlobalObject(cx), f,
+                        NS_GET_IID(nsIDOMWindow), vp);
+      }
     }
   }