Adapt to changes of Chrome 51 API changes (Part 2)

atom/browser/atom_javascript_dialog_manager.cc

@@ -26,7 +26,7 @@ void AtomJavaScriptDialogManager::RunBeforeUnloadDialog(
     bool is_reload,
     const DialogClosedCallback& callback) {
   // FIXME(zcbenz): the |message_text| is removed, figure out what should we do.
-  callback.Run(true);
+  callback.Run(true, base::ASCIIToUTF16("FIXME"));
 }
 
 }  // namespace atom