Make message center always scroll up upon notification removal

ui/message_center/message_center_switches.cc

Index: ui/message_center/message_center_switches.cc
diff --git a/ui/message_center/message_center_switches.cc b/ui/message_center/message_center_switches.cc
new file mode 100644
index 0000000000000000000000000000000000000000..0907e24db3d1e8ffd795f487369119919807f912
--- /dev/null
+++ b/ui/message_center/message_center_switches.cc
@@ -0,0 +1,15 @@
+// Copyright 2014 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 "ui/message_center/message_center_switches.h"
+
+namespace switches {
+
+// Enables message center to always move other notifications upwards when a
+// notification is removed, no matter whether the message center is displayed
+// top down or not.
+const char kEnableMessageCenterAlwaysScrollUpUponNotificationRemoval[] =
+    "enable-message-center-always-scroll-up-upon-notification-removal";
+
+}  // namespace switches