Listen to Display reconfiguration and notify DisplayObservers on Mac.

ui/views/widget/desktop_aura/desktop_screen_x11.h

Index: ui/views/widget/desktop_aura/desktop_screen_x11.h
diff --git a/ui/views/widget/desktop_aura/desktop_screen_x11.h b/ui/views/widget/desktop_aura/desktop_screen_x11.h
index a5b2a17dd835e0c133ecc47e2c82e294c18335be..ff47806eb6799e18740742b5f591e9a56d49deb6 100644
--- a/ui/views/widget/desktop_aura/desktop_screen_x11.h
+++ b/ui/views/widget/desktop_aura/desktop_screen_x11.h
@@ -5,9 +5,9 @@
 #ifndef UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_SCREEN_X11_H_
 #define UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_SCREEN_X11_H_
 
-#include "base/observer_list.h"
 #include "base/timer/timer.h"
 #include "ui/events/platform/platform_event_dispatcher.h"
+#include "ui/gfx/display_change_notifier.h"
 #include "ui/gfx/screen.h"
 #include "ui/views/views_export.h"
 
@@ -30,10 +30,6 @@ class VIEWS_EXPORT DesktopScreenX11 : public gfx::Screen,
 
   virtual ~DesktopScreenX11();
 
-  // Takes a set of displays and dispatches the screen change events to
-  // listeners. Exposed for testing.
-  void ProcessDisplayChange(const std::vector<gfx::Display>& displays);
-
   // Overridden from gfx::Screen:
   virtual bool IsDIPEnabled() OVERRIDE;
   virtual gfx::Point GetCursorScreenPoint() OVERRIDE;
@@ -86,7 +82,7 @@ class VIEWS_EXPORT DesktopScreenX11 : public gfx::Screen,
   // Dispatch().
   scoped_ptr<base::OneShotTimer<DesktopScreenX11> > configure_timer_;
 
-  ObserverList<gfx::DisplayObserver> observer_list_;
+  gfx::DisplayChangeNotifier change_notifier_;
 
   DISALLOW_COPY_AND_ASSIGN(DesktopScreenX11);
 };