Add button to add new FSP services to Files app.

ui/file_manager/file_manager/foreground/js/file_manager_commands.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.
 
 /**
  * TODO(dzvorygin): Here we use this hack, since 'hidden' is standard
  * attribute and we can't use it's setter as usual.
  * @param {boolean} value New value of hidden property.
  */
 cr.ui.Command.prototype.setHidden = function(value) {
@@ skipping 1221 matching lines @@
 CommandHandler.COMMANDS_['inspect-background'] = /** @type {Command} */ ({
   /**
    * @param {!Event} event Command event.
    * @param {!FileManager} fileManager FileManager to use.
    */
   execute: function(event, fileManager) {
     chrome.fileManagerPrivate.openInspector('background');
   },
   canExecute: CommandUtil.canExecuteAlways
 });
+
+/**
+ * Shows a suggest dialog with new services to be added to the left nav.
+ * @type {Command}
+ */
+CommandHandler.COMMANDS_['add-new-services'] = /** @type {Command} */ ({
+  /**
+   * @param {!Event} event Command event.
+   * @param {!FileManager} fileManager FileManager to use.
+   */
+  execute: function(event, fileManager) {
+    fileManager.ui.suggestAppsDialog.showProviders(function() {});
+  },
+  canExecute: CommandUtil.canExecuteAlways
+});