Introduce authentication stage changed event.

Bug: b:307846218
Change-Id: Ic338cd6f9a5bd17fe2d0879ac5a2d7de439d3a71
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5028397
Commit-Queue: Istvan Nagy <iscsi@google.com>
Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1228820}

diff --git a/ash/login/login_screen_controller.cc b/ash/login/login_screen_controller.cc
index 485a96b..845fdb6 100644
--- a/ash/login/login_screen_controller.cc
+++ b/ash/login/login_screen_controller.cc

@@ -125,7 +125,7 @@
       // Set a dummy authentication stage so that |IsAuthenticating| returns
       // true.
       LOG(WARNING) << "crbug.com/1339004 : Dummy auth state";
-      authentication_stage_ = AuthenticationStage::kDoAuthenticate;
+      SetAuthenticationStage(AuthenticationStage::kDoAuthenticate);
       base::SingleThreadTaskRunner::GetCurrentDefault()->PostDelayedTask(
           FROM_HERE,
           base::BindOnce(&LoginScreenController::OnAuthenticateComplete,
@@ -136,7 +136,7 @@
   }
 
   LOG(WARNING) << "crbug.com/1339004 : started authentication";
-  authentication_stage_ = AuthenticationStage::kDoAuthenticate;
+  SetAuthenticationStage(AuthenticationStage::kDoAuthenticate);
 
   if (authenticated_by_pin) {
     DCHECK(base::ContainsOnlyChars(password, "0123456789"));
@@ -170,7 +170,7 @@
     return;
   }
 
-  authentication_stage_ = AuthenticationStage::kDoAuthenticate;
+  SetAuthenticationStage(AuthenticationStage::kDoAuthenticate);
   client_->AuthenticateUserWithChallengeResponse(
       account_id,
       base::BindOnce(&LoginScreenController::OnAuthenticateComplete,
@@ -446,6 +446,15 @@
       ->ConfigureKioskCallbacks(launch_app, on_show_menu);
 }
 
+void LoginScreenController::SetAuthenticationStage(
+    AuthenticationStage authentication_stage) {
+  if (authentication_stage == authentication_stage_) {
+    return;
+  }
+  authentication_stage_ = authentication_stage;
+  login_data_dispatcher_.AuthenticationStageChange(authentication_stage);
+}
+
 void LoginScreenController::HandleAccelerator(
     ash::LoginAcceleratorAction action) {
   if (!client_) {
@@ -478,10 +487,10 @@
     OnAuthenticateCallback callback,
     bool success) {
   LOG(WARNING) << "crbug.com/1339004 : authentication complete";
-  authentication_stage_ = AuthenticationStage::kUserCallback;
+  SetAuthenticationStage(AuthenticationStage::kUserCallback);
   std::move(callback).Run(absl::make_optional<bool>(success));
   LOG(WARNING) << "crbug.com/1339004 : triggered callback";
-  authentication_stage_ = AuthenticationStage::kIdle;
+  SetAuthenticationStage(AuthenticationStage::kIdle);
 
   // During smart card login flow, multiple security token requests can be made.
   // If the user cancels one, all others should also be canceled.
@@ -523,7 +532,7 @@
   }
 
   // Still handle it to avoid crashes during Login/Lock/Unlock flows.
-  authentication_stage_ = AuthenticationStage::kIdle;
+  SetAuthenticationStage(AuthenticationStage::kIdle);
   SetSystemTrayVisibility(SystemTrayVisibility::kAll);
 }
 
@@ -534,14 +543,13 @@
   client_->OnLoginScreenShown();
 }
 
-std::ostream& operator<<(std::ostream& ostream,
-                         LoginScreenController::AuthenticationStage stage) {
+std::ostream& operator<<(std::ostream& ostream, AuthenticationStage stage) {
   switch (stage) {
-    case LoginScreenController::AuthenticationStage::kIdle:
+    case AuthenticationStage::kIdle:
       return ostream << "kIdle";
-    case LoginScreenController::AuthenticationStage::kDoAuthenticate:
+    case AuthenticationStage::kDoAuthenticate:
       return ostream << "kDoAuthenticate";
-    case LoginScreenController::AuthenticationStage::kUserCallback:
+    case AuthenticationStage::kUserCallback:
       return ostream << "kUserCallback";
   }
 }