Revert of Removed dependency on the UI from the NetworkPortalDetector.

chrome/browser/chromeos/login/screens/error_screen.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/chromeos/login/screens/error_screen.h"
 
 #include "base/command_line.h"
 #include "chrome/browser/chromeos/login/chrome_restart_request.h"
 #include "chrome/browser/chromeos/login/screens/error_screen_actor.h"
 #include "chrome/browser/chromeos/login/startup_utils.h"
 #include "chrome/browser/chromeos/login/wizard_controller.h"
 #include "chrome/browser/chromeos/net/network_portal_detector.h"
-#include "chrome/browser/chromeos/net/network_portal_detector_strategy.h"
 #include "chrome/browser/chromeos/settings/cros_settings.h"
 
 namespace chromeos {
 
 ErrorScreen::ErrorScreen(ScreenObserver* screen_observer,
                          ErrorScreenActor* actor)
     : WizardScreen(screen_observer),
       actor_(actor),
       parent_screen_(OobeDisplay::SCREEN_UNKNOWN),
       weak_factory_(this) {
   DCHECK(actor_);
   actor_->SetDelegate(this);
+  AddObserver(NetworkPortalDetector::Get());
 }
 
 ErrorScreen::~ErrorScreen() {
   actor_->SetDelegate(NULL);
+  RemoveObserver(NetworkPortalDetector::Get());
+}
+
+void ErrorScreen::AddObserver(Observer* observer) {
+  if (observer)
+    observers_.AddObserver(observer);
+}
+
+void ErrorScreen::RemoveObserver(Observer* observer) {
+  if (observer)
+    observers_.RemoveObserver(observer);
 }
 
 void ErrorScreen::PrepareToShow() {
 }
 
 void ErrorScreen::Show() {
   DCHECK(actor_);
   actor_->Show(parent_screen(), NULL);
 }
 
 void ErrorScreen::Hide() {
   DCHECK(actor_);
   actor_->Hide();
 }
 
 std::string ErrorScreen::GetName() const {
   return WizardController::kErrorScreenName;
 }
 
 void ErrorScreen::OnErrorShow() {
-  NetworkPortalDetector::Get()->SetStrategy(
-      PortalDetectorStrategy::STRATEGY_ID_ERROR_SCREEN);
+  FOR_EACH_OBSERVER(Observer, observers_, OnErrorScreenShow());
 }
 
 void ErrorScreen::OnErrorHide() {
-  NetworkPortalDetector::Get()->SetStrategy(
-      PortalDetectorStrategy::STRATEGY_ID_LOGIN_SCREEN);
+  FOR_EACH_OBSERVER(Observer, observers_, OnErrorScreenHide());
 }
 
 void ErrorScreen::OnLaunchOobeGuestSession() {
   DeviceSettingsService::Get()->GetOwnershipStatusAsync(
       base::Bind(&ErrorScreen::StartGuestSessionAfterOwnershipCheck,
                  weak_factory_.GetWeakPtr()));
 }
 
 void ErrorScreen::OnLoginFailure(const LoginFailure& error) {
   // The only condition leading here is guest mount failure, which should not
@@ skipping 106 matching lines @@
   }
 
   if (guest_login_performer_)
     return;
 
   guest_login_performer_.reset(new LoginPerformer(this));
   guest_login_performer_->LoginOffTheRecord();
 }
 
 }  // namespace chromeos