[Chrome OS MD] Draw a 1px separator between 2 tray items

ash/common/system/web_notification/web_notification_tray.h

 // Copyright (c) 2012 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 ASH_COMMON_SYSTEM_WEB_NOTIFICATION_WEB_NOTIFICATION_TRAY_H_
 #define ASH_COMMON_SYSTEM_WEB_NOTIFICATION_WEB_NOTIFICATION_TRAY_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
@@ skipping 27 matching lines @@
 class MessageCenterBubble;
 class MessagePopupCollection;
 }
 
 namespace ash {
 class AshPopupAlignmentDelegate;
 class SystemTray;
 class WebNotificationBubbleWrapper;
 class WebNotificationButton;
 class WmWindow;
+class WmShelfObserver;
 
 class ASH_EXPORT WebNotificationTray
     : public TrayBackgroundView,
       public views::TrayBubbleView::Delegate,
       public message_center::MessageCenterTrayDelegate,
       public views::ButtonListener,
       public base::SupportsWeakPtr<WebNotificationTray>,
       public ui::SimpleMenuModel::Delegate {
  public:
   WebNotificationTray(WmShelf* shelf,
                       WmWindow* status_area_window,
-                      SystemTray* system_tray);
+                      SystemTray* system_tray,
+                      WmShelfObserver* wm_shelf_observer);
   ~WebNotificationTray() override;
 
   // Sets the height of the system tray bubble (or legacy notification bubble)
   // from the edge of the work area so that the web notification popups don't
   // overlap with the tray. Pass 0 if no bubble is shown.
   void SetTrayBubbleHeight(int height);
 
   // Returns the current tray bubble height or 0 if there is no bubble.
   int tray_bubble_height_for_test() const;
 
@@ skipping 118 matching lines @@
   bool should_block_shelf_auto_hide_;
 
   std::unique_ptr<AshPopupAlignmentDelegate> popup_alignment_delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(WebNotificationTray);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_WEB_NOTIFICATION_WEB_NOTIFICATION_TRAY_H_