dbus: add ObjectPath type

dbus/mock_exported_object.h

Index: dbus/mock_exported_object.h
diff --git a/dbus/mock_exported_object.h b/dbus/mock_exported_object.h
index 17a36d009a22724175c23dcd16b366d0c50c6801..7deb1118d00c3d97538120e6618f5f451dc46199 100644
--- a/dbus/mock_exported_object.h
+++ b/dbus/mock_exported_object.h
@@ -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.
 
@@ -9,6 +9,7 @@
 #include <string>
 
 #include "dbus/exported_object.h"
+#include "dbus/object_path.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 namespace dbus {
@@ -18,7 +19,7 @@ class MockExportedObject : public ExportedObject {
  public:
   MockExportedObject(Bus* bus,
                      const std::string& service_name,
-                     const std::string& object_path);
+                     const ObjectPath& object_path);
   virtual ~MockExportedObject();
 
   MOCK_METHOD3(ExportMethodAndBlock,