Have OobeUI handle display observation

chrome/browser/chromeos/login/ui/login_display_host_impl.h

Index: chrome/browser/chromeos/login/ui/login_display_host_impl.h
diff --git a/chrome/browser/chromeos/login/ui/login_display_host_impl.h b/chrome/browser/chromeos/login/ui/login_display_host_impl.h
index 124f21f3bc2d5276405378477ef2abb107fe996e..e4d8862578fbefe3cf65630c2aebeb11e4933fe3 100644
--- a/chrome/browser/chromeos/login/ui/login_display_host_impl.h
+++ b/chrome/browser/chromeos/login/ui/login_display_host_impl.h
@@ -27,7 +27,6 @@
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/web_contents_observer.h"
-#include "ui/display/display_observer.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/views/widget/widget_removals_observer.h"
 #include "ui/wm/public/scoped_drag_drop_disabler.h"
@@ -50,7 +49,6 @@ class LoginDisplayHostImpl : public LoginDisplayHost,
                              public content::WebContentsObserver,
                              public chromeos::SessionManagerClient::Observer,
                              public chromeos::CrasAudioHandler::AudioObserver,
-                             public display::DisplayObserver,
                              public views::WidgetRemovalsObserver,
                              public chrome::MultiUserWindowManager::Observer {
  public:
@@ -115,12 +113,6 @@ class LoginDisplayHostImpl : public LoginDisplayHost,
   // Overridden from chromeos::CrasAudioHandler::AudioObserver:
   void OnActiveOutputNodeChanged() override;
 
-  // Overridden from display::DisplayObserver:
-  void OnDisplayAdded(const display::Display& new_display) override;
-  void OnDisplayRemoved(const display::Display& old_display) override;
-  void OnDisplayMetricsChanged(const display::Display& display,
-                               uint32_t changed_metrics) override;
-
   // Overriden from views::WidgetRemovalsObserver:
   void OnWillRemoveView(views::Widget* widget, views::View* view) override;