Replace own callback handling with Promises.

chrome/browser/resources/options/managed_user_list_data.js

 // Copyright 2014 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('options', function() {
   /**
    * ManagedUserListData class.
    * Handles requests for retrieving a list of existing managed users which are
    * supervised by the current profile. This list is cached in order to make it
    * possible to serve future requests immediately. The first request will be
    * handled asynchronously.
    * @constructor
    * @class
    */
+  // TODO(akuegel): Refactor this class by using dom promises.
   function ManagedUserListData() {
     this.callbacks_ = [];
     this.errbacks_ = [];
     this.requestInProgress_ = false;
     this.managedUsers_ = null;
   };
 
   cr.addSingletonGetter(ManagedUserListData);
 
   /**
    * Resets to the initial state of no pending requests.
    * @private
    */
   ManagedUserListData.prototype.reset_ = function() {
     this.callbacks_ = [];
     this.errbacks_ = [];
     this.requestInProgress_ = false;
   }
 
   /**
    * Receives a list of managed users and passes the list to each of the
    * callbacks.
    * @param {Array.<Object>} managedUsers An array of managed user objects.
    *     Each object is of the form:
    *       managedUser = {
    *         id: "Managed User ID",
    *         name: "Managed User Name",
    *         iconURL: "chrome://path/to/icon/image",
    *         onCurrentDevice: true or false,
+   *         nameConflict: true or false,
    *         needAvatar: true or false
    *       }
+   * @private
    */
-  ManagedUserListData.receiveExistingManagedUsers = function(managedUsers) {
-    var instance = ManagedUserListData.getInstance();
-    var i;
-    for (i = 0; i < instance.callbacks_.length; i++) {
-      instance.callbacks_[i](managedUsers);
-    }
-    instance.managedUsers_ = managedUsers;
-    instance.reset_();
+  ManagedUserListData.prototype.receiveExistingManagedUsers_ = function(
+      managedUsers) {
+    for (var i = 0; i < this.callbacks_.length; i++)
+      this.callbacks_[i](managedUsers);
+    this.managedUsers_ = managedUsers;
+    this.reset_();
   };
 
   /**
    * Called when there is a signin error when retrieving the list of managed
    * users. Calls the error callbacks which will display an appropriate error
    * message to the user.
+   * @private
    */
-  ManagedUserListData.onSigninError = function() {
-    var instance = ManagedUserListData.getInstance();
-    var i;
-    for (i = 0; i < instance.errbacks_.length; i++) {
-      instance.errbacks_[i]();
-    }
+  ManagedUserListData.prototype.onSigninError_ = function() {
+    for (var i = 0; i < this.errbacks_.length; i++)
+      this.errbacks_[i]();
     // Reset the list of managed users in order to avoid showing stale data.
-    instance.managedUsers_ = null;
-    instance.reset_();
+    this.managedUsers_ = null;
+    this.reset_();
   };
 
   /**
    * Handles the request for the list of existing managed users. If the data is
    * already available, it will call |callback| immediately. Otherwise, it
    * retrieves the list of existing managed users which is then processed in
    * receiveExistingManagedUsers().
    * @param {Object} callback The callback function which is called on success.
    * @param {Object} errback the callback function which is called on error.
+   * @private
    */
-  ManagedUserListData.requestExistingManagedUsers = function(callback,
-                                                             errback) {
-    var instance = ManagedUserListData.getInstance();
-    instance.callbacks_.push(callback);
-    instance.errbacks_.push(errback);
-    if (!instance.requestInProgress_) {
-      if (instance.managedUsers_ != null) {
-        ManagedUserListData.receiveExistingManagedUsers(instance.managedUsers_);
+  ManagedUserListData.prototype.requestExistingManagedUsers_ = function(
+      callback, errback) {
+    if (!this.requestInProgress_) {

[Bernhard Bauer, 2014/01/09 16:33:18]

Early-return if a request is in progress?

[Adrian Kuegel, 2014/01/10 09:53:43]

This is obsolete now. I already replaced my code with Promises.

+      if (this.managedUsers_ != null) {
+        callback(this.managedUsers_);
         return;
       }
-      instance.requestInProgress_ = true;
+      this.callbacks_.push(callback);
+      this.errbacks_.push(errback);
+      this.requestInProgress_ = true;
       chrome.send('requestManagedUserImportUpdate');
     }
   };
 
   /**
    * Reload the list of existing managed users. Should be called when a new
    * supervised user profile was created or a supervised user profile was
    * deleted.
+   * @private
    */
-  ManagedUserListData.reloadExistingManagedUsers = function() {
-    var instance = ManagedUserListData.getInstance();
-    if (instance.requestInProgress_)
+  ManagedUserListData.prototype.reloadExistingManagedUsers_ = function() {
+    if (this.requestInProgress_)
       return;
 
-    instance.managedUsers_ = null;
-    instance.requestInProgress_ = true;
+    this.managedUsers_ = null;
+    this.requestInProgress_ = true;
     chrome.send('requestManagedUserImportUpdate');
   };
 
+  // Forward public APIs to private implementations.
+  [
+    'onSigninError',
+    'receiveExistingManagedUsers',
+    'reloadExistingManagedUsers',
+    'requestExistingManagedUsers',
+  ].forEach(function(name) {
+    ManagedUserListData[name] = function() {
+      var instance = ManagedUserListData.getInstance();
+      return instance[name + '_'].apply(instance, arguments);
+    };
+  });
+
   // Export
   return {
     ManagedUserListData: ManagedUserListData,
   };
 });