Cros lock screen: hide user creation screen for re-auth dialog

is_user_creation_enabled needs to reset to false on cancel action.

Bug: 1163033
Change-Id: I1b1bd5643bb2829ba2af9a84eaaec6f5fee70d90
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2610089Reviewed-by: Denis Kuznetsov [CET] <antrim@chromium.org>
Commit-Queue: Yunke Zhou <yunkez@google.com>
Cr-Commit-Position: refs/heads/master@{#840163}

chrome/browser/chromeos/login/screens/user_creation_screen.cc

@@ -122,6 +122,7 @@ void UserCreationScreen::OnUserAction(const std::string& action_id) {
     context()->is_child_gaia_account_new = true;
     exit_callback_.Run(Result::CHILD_ACCOUNT_CREATE);
   } else if (action_id == kUserActionCancel) {
+    context()->is_user_creation_enabled = false;
     exit_callback_.Run(Result::CANCEL);
   } else {
     BaseScreen::OnUserAction(action_id);

chrome/browser/chromeos/login/wizard_context.h

@@ -55,8 +55,10 @@ class WizardContext {
   bool skip_to_update_for_tests = false;
 
   // Whether user creation screen is enabled (could be disabled due to disabled
-  // feature or on managed device). Set by UserCreationScreen::MaybeSkip and
-  // will be flipped to true when screen is shown.
+  // feature or on managed device). It determines the behavior of back button
+  // for GaiaScreen and OfflineLoginScreen. Value is set to true in
+  // UserCreationScreen::MaybeSkip when screen is shown and will be set to false
+  // when screen is skipped or when cancel action is called.
   bool is_user_creation_enabled = false;
 };