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

chrome/browser/extensions/extension_service.h

 // Copyright (c) 2011 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_SERVICE_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_SERVICE_H_
 #pragma once
 
 #include <map>
 #include <string>
@@ skipping 299 matching lines @@
 
   // Called only by testing.
   void ReloadExtensions();
 
   // Scan the extension directory and clean up the cruft.
   void GarbageCollectExtensions();
 
   // The App that represents the web store.
   const Extension* GetWebStoreApp();
 
+  // Sets the order the apps should be displayed in the app launcher.
+  void SetAppLauncherOrder(const std::vector<std::string>& extension_ids);
+
   // Lookup an extension by |url|.
   const Extension* GetExtensionByURL(const GURL& url);
 
   // If there is an extension for the specified url it is returned. Otherwise
   // returns the extension whose web extent contains |url|.
   const Extension* GetExtensionByWebExtent(const GURL& url);
 
   // Returns an extension that contains any URL that overlaps with the given
   // extent, if one exists.
   const Extension* GetExtensionByOverlappingWebExtent(
@@ skipping 298 matching lines @@
   FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest,
                            UpdatePendingExtensionAlreadyInstalled);
   FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest,
                            InstallAppsWithUnlimtedStorage);
   FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest,
                            InstallAppsAndCheckStorageProtection);
   DISALLOW_COPY_AND_ASSIGN(ExtensionService);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_SERVICE_H_