diff --git a/constants.h b/constants.h
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--- /dev/null
+++ b/constants.h
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+// 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_CONSTANTS_H
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_CONSTANTS_H
+
+namespace chromeos_update_engine {
+
+// The name of the marker file used to trigger powerwash when post-install
+// completes successfully so that the device is powerwashed on next reboot.
+extern const char kPowerwashMarkerFile[];
+
+// The contents of the powerwash marker file.
+extern const char kPowerwashCommand[];
+
+}  // namespace chromeos_update_engine
+
+#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_CONSTANTS_H