[NTP] Allow reordering of apps via drag and drop.

chrome/browser/extensions/extension_prefs.h

 // Copyright (c) 2010 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 CHROME_BROWSER_EXTENSIONS_EXTENSION_PREFS_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_PREFS_H_
 #pragma once
 
 #include <set>
 #include <string>
@@ skipping 233 matching lines @@
   // index a -1 value is returned.
   int GetAppLaunchIndex(const std::string& extension_id);
 
   // Sets a specific launch index for an extension with |extension_id|.
   void SetAppLaunchIndex(const std::string& extension_id, int index);
 
   // Gets the next available application launch index. This is 1 higher than the
   // highest current application launch index found.
   int GetNextAppLaunchIndex();
 
+  // Sets the order the apps should be displayed in the app launcher.
+  void SetAppLauncherOrder(const std::vector<std::string>& extension_ids);
+
   // The extension's update URL data.  If not empty, the ExtensionUpdater
   // will append a ap= parameter to the URL when checking if a new version
   // of the extension is available.
   void SetUpdateUrlData(const std::string& extension_id,
                         const std::string& data);
   std::string GetUpdateUrlData(const std::string& extension_id);
 
   // Sets a preference value that is controlled by the extension. In other
   // words, this is not a pref value *about* the extension but something
   // global the extension wants to override.
@@ skipping 132 matching lines @@
   // Used to manipulate extension preferences.
   ExtensionPrefStore* pref_store_;
 
   // The URLs of all of the toolstrips.
   URLList shelf_order_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionPrefs);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_PREFS_H_