Allow the powerwash shortcut only for devices without FRE

chrome/browser/chromeos/login/enrollment/auto_enrollment_controller.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_BROWSER_CHROMEOS_LOGIN_ENROLLMENT_AUTO_ENROLLMENT_CONTROLLER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_ENROLLMENT_AUTO_ENROLLMENT_CONTROLLER_H_
 
 #include <memory>
 #include <string>
 #include <vector>
@@ skipping 43 matching lines @@
     // FRE check explicitly required by the flag in VPD.
     EXPLICITLY_REQUIRED,
     // FRE check to be skipped, explicitly stated by the flag in VPD.
     EXPLICITLY_NOT_REQUIRED,
   };
 
   // Gets the auto-enrollment mode based on command-line flags and official
   // build status.
   static Mode GetMode();
 
+  // Returns whether the auto-enrollment check is required. When
+  // kCheckEnrollmentKey VPD entry is present, it is explicitly stating whether
+  // the forced re-enrollment is required or not. Otherwise, for backward
+  // compatibility with devices upgrading from an older version of Chrome OS,
+  // the kActivateDateKey VPD entry is queried. If it's missing, FRE is not
+  // required. This enables factories to start full guest sessions for testing,
+  // see http://crbug.com/397354 for more context. The requirement for the
+  // machine serial number to be present is a sanity-check to ensure that the
+  // VPD has actually been read successfully. If VPD read failed, the FRE check
+  // is required.
+  static FRERequirement GetFRERequirement();

[achuithb, 2017/05/23 19:59:01]

Why not have:
bool IsForcedAutoEnrollmentRequired(). That way webui_login_view doesn't need to
know about NOT_REQUIRED and EXPLICITLY_NOT_REQUIRED, etc.

+
   AutoEnrollmentController();
   ~AutoEnrollmentController();
 
   // Starts the auto-enrollment check.  Safe to call multiple times: aborts in
   // case a check is currently running or a decision has already been made.
   void Start();
 
   // Retry checking.
   void Retry();
 
@@ skipping 57 matching lines @@
   base::WeakPtrFactory<AutoEnrollmentController> client_start_weak_factory_{
       this};
   base::WeakPtrFactory<AutoEnrollmentController> weak_ptr_factory_{this};
 
   DISALLOW_COPY_AND_ASSIGN(AutoEnrollmentController);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_ENROLLMENT_AUTO_ENROLLMENT_CONTROLLER_H_