module.exports should default to an empty object.

sky/engine/core/app/Module.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sky/engine/config.h"
 #include "sky/engine/core/app/Module.h"
 
 #include "gen/sky/core/EventTargetNames.h"
 #include "sky/engine/core/app/Application.h"
 
@@ skipping 11 matching lines @@
 }
 
 const AtomicString& Module::interfaceName() const {
   return EventTargetNames::Module;
 }
 
 Application* Module::GetApplication() {
   return application();
 }
 
+void Module::setExports(ScriptState*, const ScriptValue& exports) {
+  exports_ = exports;
+}
+
+const ScriptValue& Module::exports(ScriptState* scriptState) const {
+  if (exports_.isEmpty())
+    exports_ = ScriptValue::createEmptyObject(scriptState);
+  return exports_;
+}
+
 } // namespace blink