Move MediaGalleries.getMediaFileSystems back to experimental for M22

chrome/renderer/resources/extensions/media_galleries_custom_bindings.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.
-
-// Custom bindings for the Media Gallery API.
-
-var mediaGalleriesNatives = requireNative('mediaGalleries');
-
-var chromeHidden = requireNative('chrome_hidden').GetChromeHidden();
-
-chromeHidden.registerCustomHook('mediaGalleries',
-                                function(bindingsAPI, extensionId) {
-  var apiFunctions = bindingsAPI.apiFunctions;
-
-  // getMediaFileSystems uses a custom callback so that it can instantiate and
-  // return an array of file system objects.
-  apiFunctions.setCustomCallback('getMediaFileSystems',
-                                 function(name, request, response) {
-    var result = null;
-    if (response) {
-      result = [];
-      for (var i = 0; i < response.length; i++) {
-        result.push(mediaGalleriesNatives.GetMediaFileSystemObject(
-            response[i].fsid, response[i].name));
-      }
-    }
-    if (request.callback)
-      request.callback(result);
-    request.callback = null;
-  });
-});