Makes a gap at the top boundary of message center.

ash/system/tray/tray_constants.cc

 // 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.
 
 #include "ash/system/tray/tray_constants.h"
 
 #include "third_party/skia/include/core/SkColor.h"
 
 namespace ash {
 
@@ skipping 44 matching lines @@
 const SkColor kHeaderTextColorNormal = SkColorSetARGB(0x7f, 0, 0, 0);
 const SkColor kHeaderTextColorHover = SkColorSetARGB(0xd3, 0, 0, 0);
 
 const int kTrayPopupMinWidth = 300;
 const int kTrayPopupMaxWidth = 500;
 const int kNotificationIconWidth = 40;
 // TODO(stevenjb): This calculation is wrong (http://crbug.com/163402).
 const int kTrayNotificationContentsWidth = kTrayPopupMinWidth -
     (kNotificationIconWidth + kTrayPopupPaddingHorizontal) * 2;
 
+const int kTraySpacing = 8;
+
 }  // namespace ash