If there is a device id use that instead of a new one for re-enrolling.

chrome/browser/policy/browser_policy_connector.h

 // Copyright (c) 2012 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_POLICY_BROWSER_POLICY_CONNECTOR_H_
 #define CHROME_BROWSER_POLICY_BROWSER_POLICY_CONNECTOR_H_
 #pragma once
 
 #include <string>
 
@@ skipping 60 matching lines @@
   CloudPolicySubsystem* user_cloud_policy_subsystem() {
     return user_cloud_policy_subsystem_.get();
   }
 
   // Triggers registration for device policy, using the |owner_email| account.
   // |token| is an oauth token to authenticate the registration request, and
   // |known_machine_id| is true if the server should do additional checks based
   // on the machine_id used for the request.
   void RegisterForDevicePolicy(const std::string& owner_email,
                                const std::string& token,
-                               bool known_machine_id);
+                               bool known_machine_id,
+                               bool reregister);
 
   // Returns true if this device is managed by an enterprise (as opposed to
   // a local owner).
   bool IsEnterpriseManaged();
 
   // Locks the device to an enterprise domain.
   EnterpriseInstallAttributes::LockResult LockDevice(const std::string& user);
 
   // Returns the device serial number, or an empty string if not available.
   static std::string GetSerialNumber();
@@ skipping 106 matching lines @@
 #if defined(OS_CHROMEOS)
   scoped_ptr<AppPackUpdater> app_pack_updater_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(BrowserPolicyConnector);
 };
 
 }  // namespace policy
 
 #endif  // CHROME_BROWSER_POLICY_BROWSER_POLICY_CONNECTOR_H_