Rollback feature is taken out of the flag.

chrome/browser/ui/webui/chromeos/login/reset_screen_handler.cc

 // 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.
 
 #include "chrome/browser/ui/webui/chromeos/login/reset_screen_handler.h"
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
@@ skipping 84 matching lines @@
   PrefService* prefs = g_browser_process->local_state();
   restart_required_ = !CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kFirstExecAfterBoot);
 
   reboot_was_requested_ = false;
   rollback_available_ = false;
   preparing_for_rollback_ = false;
   if (!restart_required_)  // First exec after boot.
     reboot_was_requested_ = prefs->GetBoolean(prefs::kFactoryResetRequested);
 
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kEnableRollbackOption)) {
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableRollbackOption)) {
     rollback_available_ = false;
     ShowWithParams();
   } else if (!restart_required_ && reboot_was_requested_) {
     // First exec after boot.
     chromeos::DBusThreadManager::Get()->GetUpdateEngineClient()->
         CanRollbackCheck(base::Bind(&ResetScreenHandler::OnRollbackCheck,
         weak_ptr_factory_.GetWeakPtr()));
   } else {
     // Will require restart.
     ShowWithParams();
@@ skipping 172 matching lines @@
     base::DictionaryValue params;
     params.SetInteger("uiState", kErrorUIStateRollback);
     ShowScreen(OobeUI::kScreenErrorMessage, &params);
   } else if (status.status ==
       UpdateEngineClient::UPDATE_STATUS_UPDATED_NEED_REBOOT) {
     DBusThreadManager::Get()->GetPowerManagerClient()->RequestRestart();
   }
 }
 
 }  // namespace chromeos