Revert of Flag covering Rollback removed.

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/bind.h"
+#include "base/bind_helpers.h"
+#include "base/callback.h"
 #include "base/command_line.h"
+#include "base/file_util.h"
+#include "base/files/file_path.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/metrics/histogram.h"
 #include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chromeos/login/help_app_launcher.h"
 #include "chrome/browser/chromeos/reset/metrics.h"
 #include "chrome/browser/ui/webui/chromeos/login/oobe_ui.h"
 #include "chrome/common/pref_names.h"
 #include "chromeos/chromeos_switches.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/power_manager_client.h"
 #include "chromeos/dbus/session_manager_client.h"
 #include "chromeos/dbus/update_engine_client.h"
 #include "content/public/browser/browser_thread.h"
 #include "grit/browser_resources.h"
 #include "grit/chromium_strings.h"
 #include "grit/generated_resources.h"
 #include "ui/base/l10n/l10n_util.h"
 
 namespace {
 
 const char kJsScreenPath[] = "login.ResetScreen";
 
 // Reset screen id.
 const char kResetScreen[] = "reset";
 
 const int kErrorUIStateRollback = 7;
 
+static const char kRollbackFlagFile[] = "/tmp/.enable_rollback_ui";
+
+void CheckRollbackFlagFileExists(bool *file_exists) {
+  DCHECK(content::BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());
+  *file_exists = base::PathExists(base::FilePath(kRollbackFlagFile));
+}
+
 }  // namespace
 
 namespace chromeos {
 
 ResetScreenHandler::ResetScreenHandler()
     : BaseScreenHandler(kJsScreenPath),
       delegate_(NULL),
       show_on_init_(false),
       restart_required_(true),
       reboot_was_requested_(false),
@@ skipping 54 matching lines @@
 void ResetScreenHandler::ChooseAndApplyShowScenario() {
   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::kDisableRollbackOption)) {
+  // Check Rollback flag-file.
+  scoped_ptr<bool> file_exists(new bool(false));
+  base::Closure checkfile_closure = base::Bind(
+      &CheckRollbackFlagFileExists,
+      base::Unretained(file_exists.get()));
+  base::Closure on_check_done = base::Bind(
+      &ResetScreenHandler::OnRollbackFlagFileCheckDone,
+      weak_ptr_factory_.GetWeakPtr(),
+      base::Passed(file_exists.Pass()));
+  if (!content::BrowserThread::PostBlockingPoolTaskAndReply(
+          FROM_HERE,
+          checkfile_closure,
+          on_check_done)) {
+    LOG(WARNING) << "Failed to check flag file for Rollback reset option";
+    on_check_done.Run();
+  }
+}
+
+void ResetScreenHandler::OnRollbackFlagFileCheckDone(
+    scoped_ptr<bool> file_exists) {
+  if (!(*file_exists) && !CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableRollbackOption)) {
     rollback_available_ = false;
     ShowWithParams();
   } else if (!restart_required_ && reboot_was_requested_) {
     // First exec after boot.
     PrefService* prefs = g_browser_process->local_state();
     rollback_available_ = prefs->GetBoolean(prefs::kRollbackRequested);
     ShowWithParams();
   } else {
     chromeos::DBusThreadManager::Get()->GetUpdateEngineClient()->
         CanRollbackCheck(base::Bind(&ResetScreenHandler::OnRollbackCheck,
@@ skipping 139 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