Add a disabled message for the static incognito launcher shortcut

chrome/android/java/res_template/xml/launchershortcuts.xml

 <?xml version="1.0" encoding="utf-8"?>
 <!-- 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. -->
 
 <shortcuts xmlns:android="http://schemas.android.com/apk/res/android" >
     <shortcut
         android:shortcutId="new-tab-shortcut"
         android:icon="@drawable/shortcut_newtab"
         android:shortcutShortLabel="@string/menu_new_tab" >
         <intent
             android:action="chromium.shortcut.action.OPEN_NEW_TAB"
             android:targetPackage="{{manifest_package}}"
             android:targetClass="org.chromium.chrome.browser.LauncherShortcutActivity" >
         </intent>
     </shortcut>
 
-    <!-- The "New incognito tab" shortcut is now provided as a dynamic shortcut.
-         See crbug.com/707446.
-         TODO(twellington): Either remove this XML shorcut or add a disabled
-                            message. -->
     <shortcut
         android:shortcutId="new-incognito-tab-shortcut"
         android:enabled="false"
         android:icon="@drawable/shortcut_incognito"
         android:shortcutShortLabel="@string/accessibility_tabstrip_incognito_identifier"
-        android:shortcutLongLabel="@string/menu_new_incognito_tab" >
+        android:shortcutLongLabel="@string/menu_new_incognito_tab"
+        android:shortcutDisabledMessage="@string/disabled_incognito_launcher_shortcut_message" >
         <intent
             android:action="chromium.shortcut.action.OPEN_NEW_INCOGNITO_TAB"
             android:targetPackage="{{manifest_package}}"
             android:targetClass="org.chromium.chrome.browser.LauncherShortcutActivity" >
         </intent>
     </shortcut>
 </shortcuts>