[chromeos] Fix a use-after-free problem with LoginEventObserver

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 381 matching lines @@
   if (!controller) {
     // This may happen due to SkipToLogin not being called.
     reply.SendError("Unable to access ExistingUserController");
     return;
   }
 
   if (!automation_event_queue_.get())
     automation_event_queue_.reset(new AutomationEventQueue);
 
   int observer_id = automation_event_queue_->AddObserver(
-      new LoginEventObserver(automation_event_queue_.get(),
-                             controller, this));
+      new LoginEventObserver(automation_event_queue_.get(), this));
 
   // Return the observer's id.
   DictionaryValue return_value;
   return_value.SetInteger("observer_id", observer_id);
   reply.SendSuccess(&return_value);
 }
 
 void TestingAutomationProvider::SignOut(DictionaryValue* args,
                                         IPC::Message* reply_message) {
   ash::Shell::GetInstance()->tray_delegate()->SignOut();
@@ skipping 1098 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;
 }