bindings: Fixes connect-helper to use stringifyDOMObject.

LayoutTests/http/tests/navigatorconnect/resources/connect-helper.js

Index: LayoutTests/http/tests/navigatorconnect/resources/connect-helper.js
diff --git a/LayoutTests/http/tests/navigatorconnect/resources/connect-helper.js b/LayoutTests/http/tests/navigatorconnect/resources/connect-helper.js
index fd09d020d9de44ca0852e3691a9e38f2881c4d9c..225b608d0accb51194c350b5db8f7e2041047046 100644
--- a/LayoutTests/http/tests/navigatorconnect/resources/connect-helper.js
+++ b/LayoutTests/http/tests/navigatorconnect/resources/connect-helper.js
@@ -1,3 +1,7 @@
+if ("importScripts" in self) {
+  importScripts("/resources/testharness-helpers.js");
+}
+
 self.onmessage = function(e) {
   navigator.connect(e.data.connect)
     .then(function(port) {
@@ -7,6 +11,6 @@ self.onmessage = function(e) {
         // Not all errors can be serialized as a SerializedScriptValue, so
         // convert to JSON and parse to get just the bits that certainly can.
         e.data.port.postMessage(
-          {success: false, result: JSON.parse(JSON.stringify(error))});
+          {success: false, result: JSON.parse(stringifyDOMObject(error))});
       });
 };