Provides more types of errors for output status.

ash/shell.h

Index: ash/shell.h
diff --git a/ash/shell.h b/ash/shell.h
index d57f519c1fe699be6beddbb012813f217842f795..240d838f04294b0b4f394f749f1faaff4df36b13 100644
--- a/ash/shell.h
+++ b/ash/shell.h
@@ -101,6 +101,7 @@ class ActivationController;
 class AppListController;
 class CaptureController;
 class DisplayChangeObserverX11;
+class DisplayErrorObserver;
 class DisplayManager;
 class DragDropController;
 class EventClientImpl;
@@ -433,6 +434,9 @@ class ASH_EXPORT Shell
   internal::OutputConfiguratorAnimation* output_configurator_animation() {
     return output_configurator_animation_.get();
   }
+  internal::DisplayErrorObserver* display_error_observer() {
+    return display_error_observer_.get();
+  }
 #endif  // defined(OS_CHROMEOS)
 
   RootWindowHostFactory* root_window_host_factory() {
@@ -578,6 +582,7 @@ class ASH_EXPORT Shell
   scoped_ptr<chromeos::OutputConfigurator> output_configurator_;
   scoped_ptr<internal::OutputConfiguratorAnimation>
       output_configurator_animation_;
+  scoped_ptr<internal::DisplayErrorObserver> display_error_observer_;
 
   // Receives output change events and udpates the display manager.
   scoped_ptr<internal::DisplayChangeObserverX11> display_change_observer_;