Add mock classes for Bus, ObjectProxy, and ExportedObject.

dbus/mock_bus.cc

Index: dbus/mock_bus.cc
diff --git a/dbus/mock_bus.cc b/dbus/mock_bus.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e97cd719c3d298211a55df1b09a0b6c5e1721942
--- /dev/null
+++ b/dbus/mock_bus.cc
@@ -0,0 +1,15 @@
+// Copyright (c) 2011 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 "dbus/mock_bus.h"
+
+namespace dbus {
+
+MockBus::MockBus(Bus::Options& options) : Bus(options) {
+}
+
+MockBus::~MockBus() {
+}
+
+}  // namespace dbus