Handle a non-existing promise when receiving a signin error in the SupervisedUserListData.

BUG=405709

Review URL: https://codereview.chromium.org/495843003

Cr-Commit-Position: refs/heads/master@{#291883}

chrome/browser/resources/options/supervised_user_list_data.js

@@ -31,8 +31,8 @@ cr.define('options', function() {
    *       }
    * @private
    */
-  SupervisedUserListData.prototype.receiveExistingSupervisedUsers_ = function(
-    supervisedUsers) {
+  SupervisedUserListData.prototype.receiveExistingSupervisedUsers_ =
+      function(supervisedUsers) {
     if (!this.promise_) {
       this.onDataChanged_(supervisedUsers);
       return;
@@ -46,7 +46,9 @@ cr.define('options', function() {
    * @private
    */
   SupervisedUserListData.prototype.onSigninError_ = function() {
-    assert(this.promise_);
+    if (!this.promise_) {
+      return;
+    }
     this.reject_();
     this.resetPromise_();
   };

chrome/browser/ui/webui/options/manage_profile_browsertest.js

@@ -341,14 +341,7 @@ TEST_F('ManageProfileUITest', 'NoCreateConfirmationOnError', function() {
 });
 
 // The name and email should be inserted into the confirmation dialog.
-// Disbaled because of flakiness on Mac: crbug.com/405709
-GEN('#if defined(OS_MACOSX)');
-GEN('#define MAYBE_CreateConfirmationText \\');
-GEN('    DISABLED_CreateConfirmationText');
-GEN('#else');
-GEN('#define MAYBE_CreateConfirmationText CreateConfirmationText');
-GEN('#endif');
-TEST_F('ManageProfileUITest', 'MAYBE_CreateConfirmationText', function() {
+TEST_F('ManageProfileUITest', 'CreateConfirmationText', function() {
   var self = this;
   var custodianEmail = 'foo@example.com';