diff --git a/clock.h b/clock.h
new file mode 100644
index 0000000..027bcff
--- /dev/null
+++ b/clock.h
@@ -0,0 +1,28 @@
+// Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_CLOCK_H__
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_CLOCK_H__
+
+#include "update_engine/clock_interface.h"
+
+namespace chromeos_update_engine {
+
+// Implements a clock.
+class Clock : public ClockInterface {
+ public:
+  Clock() {}
+
+  virtual base::Time GetWallclockTime();
+
+  virtual base::Time GetMonotonicTime();
+
+ private:
+
+  DISALLOW_COPY_AND_ASSIGN(Clock);
+};
+
+}  // namespace chromeos_update_engine
+
+#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_CLOCK_H__