cros: Remove unused WizardController::Observer.

chrome/browser/chromeos/login/wizard_controller.h

Index: chrome/browser/chromeos/login/wizard_controller.h
diff --git a/chrome/browser/chromeos/login/wizard_controller.h b/chrome/browser/chromeos/login/wizard_controller.h
index b5adfc9762eb148c8eced4b5704905ba00eb12c8..8f52e645ecb173d2ab7242f1ffe4912d32cc187e 100644
--- a/chrome/browser/chromeos/login/wizard_controller.h
+++ b/chrome/browser/chromeos/login/wizard_controller.h
@@ -58,16 +58,6 @@ class WizardController : public BaseScreenDelegate,
                          public NetworkScreen::Delegate,
                          public HIDDetectionScreen::Delegate {
  public:
-  // Observes screen changes.
-  class Observer {
-   public:
-    // Called before a screen change happens.
-    virtual void OnScreenChanged(BaseScreen* next_screen) = 0;
-
-    // Called after the browser session has started.
-    virtual void OnSessionStart() = 0;
-  };
-
   WizardController(LoginDisplayHost* host, OobeUI* oobe_ui);
   ~WizardController() override;
 
@@ -109,13 +99,6 @@ class WizardController : public BaseScreenDelegate,
   pairing_chromeos::SharkConnectionListener*
   GetSharkConnectionListenerForTesting();
 
-  // Adds and removes an observer.
-  void AddObserver(Observer* observer);
-  void RemoveObserver(Observer* observer);
-
-  // Called right after the browser session has started.
-  void OnSessionStart();
-
   // Skip update, go straight to enrollment after EULA is accepted.
   void SkipUpdateEnrollAfterEula();
 
@@ -374,8 +357,6 @@ class WizardController : public BaseScreenDelegate,
   // user Sign-In completed.
   base::Time time_oobe_started_;
 
-  base::ObserverList<Observer> observer_list_;
-
   // Whether OOBE has yet been marked as completed.
   bool oobe_marked_completed_ = false;