Make spacing between uber tray items consistent with UI spec.

ash/system/tray/system_tray_item.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_SYSTEM_TRAY_SYSTEM_TRAY_ITEM_H_
 #define ASH_SYSTEM_TRAY_SYSTEM_TRAY_ITEM_H_
 
 #include "ash/ash_export.h"
 #include "ash/system/user/login_status.h"
 #include "ash/wm/shelf_types.h"
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 
 namespace views {
 class View;
 }
 
 namespace ash {
 
+namespace internal {
+class TrayItemView;
+}
+
 class ASH_EXPORT SystemTrayItem {
  public:
   SystemTrayItem();
   virtual ~SystemTrayItem();
 
   // Create* functions may return NULL if nothing should be displayed for the
   // type of view. The default implementations return NULL.
 
   // Returns a view to be displayed in the system tray. If this returns NULL,
   // then this item is not displayed in the tray.
@@ skipping 63 matching lines @@
   void HideNotificationView();
 
  private:
 
   DISALLOW_COPY_AND_ASSIGN(SystemTrayItem);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TRAY_SYSTEM_TRAY_ITEM_H_