mini_installer code cleanups (no functional changes).

chrome/installer/mini_installer/exit_code.h

+// Copyright 2014 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.
+
+#ifndef CHROME_INSTALLER_MINI_INSTALLER_EXIT_CODE_H_
+#define CHROME_INSTALLER_MINI_INSTALLER_EXIT_CODE_H_
+
+namespace mini_installer {
+
+// mini_installer process exit codes (the underlying type is uint32_t).
+enum ExitCode {
+  SUCCESS_EXIT_CODE = 0,
+  GENERIC_ERROR = 1,
+  // The next three generic values are here for historic reasons. New additions
+  // should have values strictly greater than them. This is to prevent
+  // collisions with setup.exe's installer::InstallStatus enum since the two are
+  // surfaced similarly by Google Update.
+  GENERIC_INITIALIZATION_FAILURE = 101,
+  GENERIC_UNPACKING_FAILURE = 102,
+  GENERIC_SETUP_FAILURE = 103,
+};
+
+}  // namespace mini_installer
+
+#endif  // CHROME_INSTALLER_MINI_INSTALLER_EXIT_CODE_H_