Creates notifications for display resolution change.

ash/shell.h

Index: ash/shell.h
diff --git a/ash/shell.h b/ash/shell.h
index c3adade53bc6522b1c4fc1dc0376c4596a49202e..ae08e7b534a020a07a4c23edde0df9f322d80061 100644
--- a/ash/shell.h
+++ b/ash/shell.h
@@ -115,6 +115,7 @@ class MouseCursorEventFilter;
 class OutputConfiguratorAnimation;
 class OverlayEventFilter;
 class ResizeShadowController;
+class ResolutionNotificationController;
 class RootWindowController;
 class RootWindowLayoutManager;
 class ScopedTargetRootWindow;
@@ -450,6 +451,11 @@ class ASH_EXPORT Shell
   }
 #endif  // defined(OS_CHROMEOS) && defined(USE_X11)
 
+  internal::ResolutionNotificationController*
+      resolution_notification_controller() {
+    return resolution_notification_controller_.get();
+  }
+
   RootWindowHostFactory* root_window_host_factory() {
     return root_window_host_factory_.get();
   }
@@ -607,6 +613,9 @@ class ASH_EXPORT Shell
   scoped_ptr<internal::DisplayChangeObserverX11> display_change_observer_;
 #endif  // defined(OS_CHROMEOS) && defined(USE_X11)
 
+  scoped_ptr<internal::ResolutionNotificationController>
+      resolution_notification_controller_;
+
   // |native_cursor_manager_| is owned by |cursor_manager_|, but we keep a
   // pointer to vend to test code.
   AshNativeCursorManager* native_cursor_manager_;