Observes work area change and auto-hide for notifications.

ash/shelf/shelf_layout_manager.h

Index: ash/shelf/shelf_layout_manager.h
diff --git a/ash/shelf/shelf_layout_manager.h b/ash/shelf/shelf_layout_manager.h
index 939a057e4be177705107d15560d63fb42818313e..e2d676dc74d9f3f28b610f704cedcb69e4c8dd19 100644
--- a/ash/shelf/shelf_layout_manager.h
+++ b/ash/shelf/shelf_layout_manager.h
@@ -74,6 +74,10 @@ class ASH_EXPORT ShelfLayoutManager :
   // settings see ash::switches::UseAlternateShelfLayout).
   static const int kShelfSize;
 
+  // Returns the preferred size for the shelf (either kLauncherPreferredSize or
+  // kShelfSize).
+  static int GetPreferredShelfSize();
+
   explicit ShelfLayoutManager(ShelfWidget* shelf);
   virtual ~ShelfLayoutManager();