[cros] pyauto.CancelOOBEUpdate always returns a non-empty dict with 'next_screen'.

chrome/browser/automation/testing_automation_provider_chromeos.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/automation/testing_automation_provider.h"
 
 #include "ash/shell.h"
 #include "ash/shell_delegate.h"
 #include "ash/system/tray/system_tray_delegate.h"
 #include "base/command_line.h"
@@ skipping 266 matching lines @@
   }
   // Observer will delete itself.
   new WizardControllerObserver(wizard_controller, this, reply_message);
   wizard_controller->GetEulaScreen()->OnExit(accepted, usage_stats_reporting);
 }
 
 void TestingAutomationProvider::CancelOOBEUpdate(DictionaryValue* args,
                                                  IPC::Message* reply_message) {
   WizardController* wizard_controller = WizardController::default_controller();
   if (wizard_controller && wizard_controller->IsOobeCompleted()) {
-    AutomationJSONReply(this, reply_message).SendSuccess(NULL);
+    // Update already finished.
+    scoped_ptr<DictionaryValue> return_value(new DictionaryValue);
+    return_value->SetString("next_screen",
+                            WizardController::kLoginScreenName);
+    AutomationJSONReply(this, reply_message).SendSuccess(return_value.get());
     return;
   }
   if (!wizard_controller || wizard_controller->current_screen()->GetName() !=
           WizardController::kUpdateScreenName) {
     AutomationJSONReply(this, reply_message).SendError(
         "Update screen not active.");
     return;
   }
   // Observer will delete itself.
   new WizardControllerObserver(wizard_controller, this, reply_message);
@@ skipping 1157 matching lines @@
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->
       AddObserver(power_manager_observer_);
 }
 
 void TestingAutomationProvider::RemoveChromeosObservers() {
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->
       RemoveObserver(power_manager_observer_);
   delete power_manager_observer_;
   power_manager_observer_ = NULL;
 }