Fix for bug 603677 (Crash on startup due to GetProto on an XPCWrappedNative being null with Bugzilla Tweaks jetpack installed), compartments followup. r=mrbkap.

--HG--
extra : rebase_source : 884494ce295e8e2222de4f3bafb02d4a96e2bcc2

js/src/xpconnect/wrappers/WrapperFactory.cpp

@@ -109,7 +109,7 @@ WrapperFactory::PrepareForWrapping(JSContext *cx, JSObject *scope, JSObject *obj
     XPCWrappedNative *wn = static_cast<XPCWrappedNative *>(xpc_GetJSPrivate(obj));
 
     // We know that DOM objects only allow one object, we can return early.
-    if (wn->GetProto()->ClassIsDOMObject())
+    if (wn->HasProto() && wn->GetProto()->ClassIsDOMObject())
         return DoubleWrap(cx, obj, flags);
 
     XPCCallContext ccx(JS_CALLER, cx, obj);