Make Hands-Off Zero-Touch Enrollment compatibile with tests

chrome/browser/chromeos/login/screens/screen_exit_code.h

 // Copyright 2017 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_BROWSER_CHROMEOS_LOGIN_SCREENS_SCREEN_EXIT_CODE_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_SCREEN_EXIT_CODE_H_
 
 #include <string>
 
 namespace chromeos {
 
 // Each login screen or a view shown within login wizard view is itself a
 // state. Upon exit each view returns one of the results by calling
 // the BaseScreenDelegate::OnExit() method. Depending on the result and the
 // current view or state the login wizard decides what is the next view to show.
 //
 // There must be an exit code for each way to exit the screen for each screen.
 //
 // Numeric ids are provided to facilitate interpretation of log files only,
 // they are subject to change without notice.
 enum class ScreenExitCode {
   // "Continue" was pressed on network screen and network is online.
   NETWORK_CONNECTED = 0,
   HID_DETECTION_COMPLETED = 1,
   // Connection failed while trying to load a WebPageScreen.
   CONNECTION_FAILED = 2,
   UPDATE_INSTALLED = 3,
+  // This exit code means EITHER that there was no update, OR that there
+  // was an update, but that it was not a "critical" update. "Critical" updates
+  // are those that have a deadline and require the device to reboot.
   UPDATE_NOUPDATE = 4,
   UPDATE_ERROR_CHECKING_FOR_UPDATE = 5,
   UPDATE_ERROR_UPDATING = 6,
   USER_IMAGE_SELECTED = 7,
   EULA_ACCEPTED = 8,
   EULA_BACK = 9,
   ENTERPRISE_AUTO_ENROLLMENT_CHECK_COMPLETED = 10,
   ENTERPRISE_ENROLLMENT_COMPLETED = 11,
   ENTERPRISE_ENROLLMENT_BACK = 12,
   RESET_CANCELED = 13,
@@ skipping 11 matching lines @@
   ENCRYPTION_MIGRATION_FINISHED = 25,
   ENCRYPTION_MIGRATION_SKIPPED = 26,
   EXIT_CODES_COUNT  // not a real code, must be the last
 };
 
 std::string ExitCodeToString(ScreenExitCode code);
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_SCREEN_EXIT_CODE_H_