Add error handling for supervised user import flow.

chrome/browser/resources/options/managed_user_list_data.js

Index: chrome/browser/resources/options/managed_user_list_data.js
diff --git a/chrome/browser/resources/options/managed_user_list_data.js b/chrome/browser/resources/options/managed_user_list_data.js
new file mode 100644
index 0000000000000000000000000000000000000000..f774f70751937fe5075157acf31d052a795d78b7
--- /dev/null
+++ b/chrome/browser/resources/options/managed_user_list_data.js
@@ -0,0 +1,115 @@
+// Copyright 2013 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
+   */
+  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,
+   *         needAvatar: true or false
+   *       }
+   */
+  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_();
+  };
+
+  /**
+   * 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.
+   */
+  ManagedUserListData.onSigninError = function() {
+    var instance = ManagedUserListData.getInstance();
+    var i;
+    for (i = 0; i < instance.errbacks_.length; i++) {
+      instance.errbacks_[i]();
+    }
+    // Reset the list of managed users in order to avoid showing stale data.
+    instance.managedUsers_ = null;
+    instance.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.
+   */
+  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_);
+        return;
+      }
+      instance.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.
+   */
+  ManagedUserListData.reloadExistingManagedUsers = function() {
+    var instance = ManagedUserListData.getInstance();
+    if (instance.requestInProgress_)
+      return;
+
+    instance.managedUsers_ = null;
+    instance.requestInProgress_ = true;
+    chrome.send('requestManagedUserImportUpdate');
+  };
+
+  // Export
+  return {
+    ManagedUserListData: ManagedUserListData,
+  };
+});