dbus: add ObjectPath type

dbus/mock_exported_object.cc

Index: dbus/mock_exported_object.cc
diff --git a/dbus/mock_exported_object.cc b/dbus/mock_exported_object.cc
index 0fd4f2e4bab72aa501318f4ca3d7f597c7c5da48..f49cd3d733bc631e956a05bef35a7b90b1c0c841 100644
--- a/dbus/mock_exported_object.cc
+++ b/dbus/mock_exported_object.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -8,7 +8,7 @@ namespace dbus {
 
 MockExportedObject::MockExportedObject(Bus* bus,
                                        const std::string& service_name,
-                                       const std::string& object_path)
+                                       const ObjectPath& object_path)
     : ExportedObject(bus, service_name, object_path) {
 }