exo: Add notification surface to manager after commit

components/exo/notification_surface.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_EXO_NOTIFICATION_SURFACE_H_
 #define COMPONENTS_EXO_NOTIFICATION_SURFACE_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 29 matching lines @@
 
   // Overridden from SurfaceObserver:
   void OnSurfaceDestroying(Surface* surface) override;
 
  private:
   NotificationSurfaceManager* const manager_;  // Not owned.
   Surface* surface_;                           // Not owned.
   const std::string notification_id_;
 
   std::unique_ptr<aura::Window> window_;
+  bool added_to_manager_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(NotificationSurface);
 };
 
 }  // namespace exo
 
 #endif  // COMPONENTS_EXO_NOTIFICATION_SURFACE_H_