Revert of Removed dependency on the UI from the NetworkPortalDetector.

chrome/browser/chromeos/login/screens/error_screen.h

 // 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_ERROR_SCREEN_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_ERROR_SCREEN_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
+#include "base/observer_list.h"
 #include "chrome/browser/chromeos/login/login_performer.h"
 #include "chrome/browser/chromeos/login/oobe_display.h"
 #include "chrome/browser/chromeos/login/screens/error_screen_actor_delegate.h"
 #include "chrome/browser/chromeos/login/screens/wizard_screen.h"
 #include "chrome/browser/chromeos/settings/device_settings_service.h"
 
 namespace chromeos {
 
 class ScreenObserver;
 
 // Controller for the error screen.
 class ErrorScreen : public WizardScreen,
                     public ErrorScreenActorDelegate,
                     public LoginPerformer::Delegate {
  public:
+  class Observer {
+   public:
+    virtual ~Observer() {}
+    virtual void OnErrorScreenShow() = 0;
+    virtual void OnErrorScreenHide() = 0;
+  };
+
   enum UIState {
     UI_STATE_UNKNOWN = 0,
     UI_STATE_UPDATE,
     UI_STATE_SIGNIN,
     UI_STATE_LOCALLY_MANAGED,
     UI_STATE_KIOSK_MODE,
     UI_STATE_LOCAL_STATE_ERROR,
     UI_STATE_AUTO_ENROLLMENT_ERROR,
   };
 
   enum ErrorState {
     ERROR_STATE_UNKNOWN = 0,
     ERROR_STATE_PORTAL,
     ERROR_STATE_OFFLINE,
     ERROR_STATE_PROXY,
     ERROR_STATE_AUTH_EXT_TIMEOUT,
     ERROR_STATE_KIOSK_ONLINE
   };
 
   ErrorScreen(ScreenObserver* screen_observer, ErrorScreenActor* actor);
   virtual ~ErrorScreen();
 
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
   // WizardScreen implementation.
   virtual void PrepareToShow() OVERRIDE;
   virtual void Show() OVERRIDE;
   virtual void Hide() OVERRIDE;
   virtual std::string GetName() const OVERRIDE;
 
   // ErrorScreenActorDelegate implementation:
   virtual void OnErrorShow() OVERRIDE;
   virtual void OnErrorHide() OVERRIDE;
   virtual void OnLaunchOobeGuestSession() OVERRIDE;
@@ skipping 40 matching lines @@
  private:
   // Handles the response of an ownership check and starts the guest session if
   // applicable.
   void StartGuestSessionAfterOwnershipCheck(
       DeviceSettingsService::OwnershipStatus ownership_status);
 
   ErrorScreenActor* actor_;
 
   OobeDisplay::Screen parent_screen_;
 
+  base::WeakPtrFactory<ErrorScreen> weak_factory_;
+
+  ObserverList<Observer> observers_;
+
   scoped_ptr<LoginPerformer> guest_login_performer_;
 
-  base::WeakPtrFactory<ErrorScreen> weak_factory_;
-
   DISALLOW_COPY_AND_ASSIGN(ErrorScreen);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_ERROR_SCREEN_H_