[NTP4] Experiment for adding Chrome Web Store link to footer.

chrome/browser/resources/ntp4/apps_page.js

 // 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.
 
 cr.define('ntp4', function() {
   'use strict';
 
   var localStrings = new LocalStrings;
 
   var APP_LAUNCH = {
     // The histogram buckets (keep in sync with extension_constants.h).
     NTP_APPS_MAXIMIZED: 0,
     NTP_APPS_COLLAPSED: 1,
     NTP_APPS_MENU: 2,
     NTP_MOST_VISITED: 3,
     NTP_RECENTLY_CLOSED: 4,
-    NTP_APP_RE_ENABLE: 16
+    NTP_APP_RE_ENABLE: 16,
+    NTP_WEBSTORE_FOOTER: 18,
   };
 
   // Histogram buckets for UMA tracking of where a DnD drop came from.
   var DRAG_SOURCE = {
     SAME_APPS_PANE: 0,
     OTHER_APPS_PANE: 1,
     MOST_VISITED_PANE: 2,
     BOOKMARKS_PANE: 3,
     OUTSIDE_NTP: 4
   };
@@ skipping 866 matching lines @@
     appNotificationChanged: appNotificationChanged,
     AppsPage: AppsPage,
     launchAppAfterEnable: launchAppAfterEnable,
   };
 });
 
 // TODO(estade): update the content handlers to use ntp namespace instead of
 // making these global.
 var appNotificationChanged = ntp4.appNotificationChanged;
 var launchAppAfterEnable = ntp4.launchAppAfterEnable;