Fixed a possible memory leak and support null pointers in AutomationEventObservers' NotifyEvent.

chrome/browser/automation/automation_event_observers_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/automation_event_observers.h"
 #include "chrome/browser/chromeos/login/existing_user_controller.h"
 
 LoginEventObserver::LoginEventObserver(
     AutomationEventQueue* event_queue,
     chromeos::ExistingUserController* controller)
@@ skipping 11 matching lines @@
 void LoginEventObserver::OnLoginSuccess(const std::string& username,
                                         const std::string& password,
                                         bool pending_requests,
                                         bool using_oauth) {
   _NotifyLoginEvent(std::string());
 }
 
 void LoginEventObserver::_NotifyLoginEvent(const std::string& error_string) {
   DictionaryValue* dict = new DictionaryValue;
   dict->SetString("type", "login_event");
-  dict->SetInteger("observer_id", GetId());
   if (error_string.length())
     dict->SetString("error_string", error_string);
   NotifyEvent(dict);
   controller_->set_login_status_consumer(NULL);
   RemoveIfDone();
 }