Make ui::DisplayConfigurator a singleton

ash/shell.h

Index: ash/shell.h
diff --git a/ash/shell.h b/ash/shell.h
index 14b7fd48fae11a4f575dd74faef7846c11b7cb85..4bbf75681685f7028abde9cc8bb1092721629981 100644
--- a/ash/shell.h
+++ b/ash/shell.h
@@ -519,7 +519,7 @@ class ASH_EXPORT Shell : public SystemModalContainerEventFilterDelegate,
 #if defined(OS_CHROMEOS)
   // TODO(oshima): Move these objects to DisplayController.
   ui::DisplayConfigurator* display_configurator() {
-    return display_configurator_.get();
+    return display_configurator_;
   }
   DisplayConfiguratorAnimation* display_configurator_animation() {
     return display_configurator_animation_.get();
@@ -724,7 +724,8 @@ class ASH_EXPORT Shell : public SystemModalContainerEventFilterDelegate,
       last_window_closed_logout_reminder_;
   scoped_ptr<VirtualKeyboardController> virtual_keyboard_controller_;
   // Controls video output device state.
-  scoped_ptr<ui::DisplayConfigurator> display_configurator_;
+  // Bare pointer as is a singleton.
+  ui::DisplayConfigurator* display_configurator_;
   scoped_ptr<DisplayConfiguratorAnimation> display_configurator_animation_;
   scoped_ptr<DisplayErrorObserver> display_error_observer_;
   scoped_ptr<ProjectingObserver> projecting_observer_;