port to use centralized constants files, and add input validation

mock_system_utils.h

Index: mock_system_utils.h
diff --git a/mock_system_utils.h b/mock_system_utils.h
new file mode 100644
index 0000000000000000000000000000000000000000..75b70d62622f2f96becccd0267b9f931b4e01759
--- /dev/null
+++ b/mock_system_utils.h
@@ -0,0 +1,23 @@
+// Copyright (c) 2010 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 LOGIN_MANAGER_MOCK_SYSTEM_UTILS_H_
+#define LOGIN_MANAGER_MOCK_SYSTEM_UTILS_H_
+
+#include "login_manager/system_utils.h"
+
+#include <unistd.h>
+#include <gmock/gmock.h>
+
+namespace login_manager {
+class MockSystemUtils : public SystemUtils {
+ public:
+  MockSystemUtils() {}
+  ~MockSystemUtils() {}
+  MOCK_METHOD2(kill, int(pid_t pid, int signal));
+  MOCK_METHOD1(child_is_gone, bool(pid_t child_spec));
+};
+}  // namespace login_manager
+
+#endif  // LOGIN_MANAGER_MOCK_SYSTEM_UTILS_H_