Allow multiple consumers in ExistingUserController

Support having multiple AuthStatusConsumer's in
ExistingUserController.

This is a preparation CL for implementing a browsertest that needs to
subscribe itself as a "consumer" without suppressing the default
consumer functionality (LoginDisplayHostMojo).

Bug: 1033936
Change-Id: I97e6869c105bcddc6263f6bc201ff370a03d41dd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2315336Reviewed-by: Denis Kuznetsov [CET] <antrim@chromium.org>
Commit-Queue: Maksim Ivanov <emaxx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#791260}

chrome/browser/chromeos/login/existing_user_controller.cc

@@ -1017,8 +1017,8 @@ void ExistingUserController::OnAuthFailure(const AuthFailure& failure) {
   // attempt.
   ChromeUserManager::Get()->ResetUserFlow(last_login_attempt_account_id_);
 
-  if (auth_status_consumer_)
-    auth_status_consumer_->OnAuthFailure(failure);
+  for (auto& auth_status_consumer : auth_status_consumers_)
+    auth_status_consumer.OnAuthFailure(failure);
 
   ClearActiveDirectoryState();
   ClearRecordedNames();
@@ -1167,11 +1167,10 @@ void ExistingUserController::OnProfilePrepared(Profile* profile,
   user_manager::known_user::SetIsEnterpriseManaged(user_context.GetAccountId(),
                                                    is_enterprise_managed);
 
-  // Inform |auth_status_consumer_| about successful login.
+  // Inform |auth_status_consumers_| about successful login.
   // TODO(nkostylev): Pass UserContext back crbug.com/424550
-  if (auth_status_consumer_) {
-    auth_status_consumer_->OnAuthSuccess(user_context);
-  }
+  for (auto& auth_status_consumer : auth_status_consumers_)
+    auth_status_consumer.OnAuthSuccess(user_context);
 }
 
 void ExistingUserController::OnOffTheRecordAuthSuccess() {
@@ -1183,8 +1182,8 @@ void ExistingUserController::OnOffTheRecordAuthSuccess() {
 
   UserSessionManager::GetInstance()->CompleteGuestSessionLogin(guest_mode_url_);
 
-  if (auth_status_consumer_)
-    auth_status_consumer_->OnOffTheRecordAuthSuccess();
+  for (auto& auth_status_consumer : auth_status_consumers_)
+    auth_status_consumer.OnOffTheRecordAuthSuccess();
 }
 
 void ExistingUserController::OnPasswordChangeDetected(
@@ -1201,8 +1200,8 @@ void ExistingUserController::OnPasswordChangeDetected(
     return;
   }
 
-  if (auth_status_consumer_)
-    auth_status_consumer_->OnPasswordChangeDetected(user_context);
+  for (auto& auth_status_consumer : auth_status_consumers_)
+    auth_status_consumer.OnPasswordChangeDetected(user_context);
 
   ShowPasswordChangedDialog(user_context);
 }
@@ -1356,8 +1355,8 @@ void ExistingUserController::WhiteListCheckFailed(const std::string& email) {
 
   GetLoginDisplay()->ShowWhitelistCheckFailedError();
 
-  if (auth_status_consumer_) {
-    auth_status_consumer_->OnAuthFailure(
+  for (auto& auth_status_consumer : auth_status_consumers_) {
+    auth_status_consumer.OnAuthFailure(
         AuthFailure(AuthFailure::WHITELIST_CHECK_FAILED));
   }
 
@@ -1396,6 +1395,16 @@ void ExistingUserController::DeviceSettingsChanged() {
   }
 }
 
+void ExistingUserController::AddLoginStatusConsumer(
+    AuthStatusConsumer* consumer) {
+  auth_status_consumers_.AddObserver(consumer);
+}
+
+void ExistingUserController::RemoveLoginStatusConsumer(
+    const AuthStatusConsumer* consumer) {
+  auth_status_consumers_.RemoveObserver(consumer);
+}
+
 LoginPerformer::AuthorizationMode ExistingUserController::auth_mode() const {
   if (login_performer_)
     return login_performer_->auth_mode();

chrome/browser/chromeos/login/existing_user_controller.h

@@ -15,6 +15,7 @@
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
+#include "base/observer_list.h"
 #include "base/scoped_observer.h"
 #include "base/strings/string16.h"
 #include "base/time/time.h"
@@ -126,10 +127,9 @@ class ExistingUserController : public LoginDisplay::Delegate,
                const content::NotificationSource& source,
                const content::NotificationDetails& details) override;
 
-  // Set a delegate that we will pass AuthStatusConsumer events to.
-  void set_login_status_consumer(AuthStatusConsumer* consumer) {
-    auth_status_consumer_ = consumer;
-  }
+  // Add/remove a delegate that we will pass AuthStatusConsumer events to.
+  void AddLoginStatusConsumer(AuthStatusConsumer* consumer);
+  void RemoveLoginStatusConsumer(const AuthStatusConsumer* consumer);
 
   // Returns value of LoginPerformer::auth_mode() (cached if performer is
   // destroyed).
@@ -339,9 +339,9 @@ class ExistingUserController : public LoginDisplay::Delegate,
   // Used to execute login operations.
   std::unique_ptr<LoginPerformer> login_performer_;
 
-  // Delegate to forward all authentication status events to.
+  // Delegates to forward all authentication status events to.
   // Tests can use this to receive authentication status events.
-  AuthStatusConsumer* auth_status_consumer_ = nullptr;
+  base::ObserverList<AuthStatusConsumer> auth_status_consumers_;
 
   // AccountId of the last login attempt.
   AccountId last_login_attempt_account_id_ = EmptyAccountId();

chrome/browser/chromeos/login/security_token_login_browsertest.cc

@@ -121,16 +121,15 @@ class ChallengeResponseFakeCryptohomeClient : public FakeCryptohomeClient {
 class AuthFailureWaiter final : public AuthStatusConsumer {
  public:
   AuthFailureWaiter() {
-    ExistingUserController::current_controller()->set_login_status_consumer(
-        this);
+    ExistingUserController::current_controller()->AddLoginStatusConsumer(this);
   }
 
   AuthFailureWaiter(const AuthFailureWaiter&) = delete;
   AuthFailureWaiter& operator=(const AuthFailureWaiter&) = delete;
 
   ~AuthFailureWaiter() override {
-    ExistingUserController::current_controller()->set_login_status_consumer(
-        nullptr);
+    ExistingUserController::current_controller()->RemoveLoginStatusConsumer(
+        this);
   }
 
   AuthFailure::FailureReason Wait() {

chrome/browser/chromeos/login/ui/login_display_host_mojo.cc

@@ -572,7 +572,7 @@ void LoginDisplayHostMojo::CreateExistingUserController() {
   login_display_->set_delegate(existing_user_controller_.get());
 
   // We need auth attempt results to notify views-based login screen.
-  existing_user_controller_->set_login_status_consumer(this);
+  existing_user_controller_->AddLoginStatusConsumer(this);
 }
 
 }  // namespace chromeos

chrome/browser/chromeos/policy/device_local_account_browsertest.cc

@@ -2062,7 +2062,7 @@ IN_PROC_BROWSER_TEST_F(DeviceLocalAccountTest, TermsOfServiceWithLocaleSwitch) {
   chromeos::ExistingUserController* controller =
       chromeos::ExistingUserController::current_controller();
   ASSERT_TRUE(controller);
-  controller->set_login_status_consumer(&login_status_consumer);
+  controller->AddLoginStatusConsumer(&login_status_consumer);
 
   // Manually select a different keyboard layout and click the enter button to
   // start the session.
@@ -2073,7 +2073,7 @@ IN_PROC_BROWSER_TEST_F(DeviceLocalAccountTest, TermsOfServiceWithLocaleSwitch) {
   // Spin the loop until the login observer fires. Then, unregister the
   // observer.
   login_wait_run_loop.Run();
-  controller->set_login_status_consumer(NULL);
+  controller->RemoveLoginStatusConsumer(&login_status_consumer);
 
   // Verify that the Terms of Service screen is being shown.
   chromeos::WizardController* wizard_controller =
@@ -2649,9 +2649,9 @@ IN_PROC_BROWSER_TEST_P(TermsOfServiceDownloadTest, TermsOfServiceScreen) {
   chromeos::ExistingUserController* controller =
       chromeos::ExistingUserController::current_controller();
   ASSERT_TRUE(controller);
-  controller->set_login_status_consumer(&login_status_consumer);
+  controller->AddLoginStatusConsumer(&login_status_consumer);
   login_wait_run_loop.Run();
-  controller->set_login_status_consumer(NULL);
+  controller->RemoveLoginStatusConsumer(&login_status_consumer);
 
   // Verify that the Terms of Service screen is being shown.
   chromeos::WizardController* wizard_controller =
@@ -2765,9 +2765,9 @@ IN_PROC_BROWSER_TEST_P(TermsOfServiceDownloadTest, DeclineTermsOfService) {
   chromeos::ExistingUserController* controller =
       chromeos::ExistingUserController::current_controller();
   ASSERT_TRUE(controller);
-  controller->set_login_status_consumer(&login_status_consumer);
+  controller->AddLoginStatusConsumer(&login_status_consumer);
   login_wait_run_loop.Run();
-  controller->set_login_status_consumer(NULL);
+  controller->RemoveLoginStatusConsumer(&login_status_consumer);
 
   // Verify that the Terms of Service screen is being shown.
   chromeos::WizardController* wizard_controller =

chromeos/login/auth/auth_status_consumer.h

@@ -10,6 +10,7 @@
 #include "base/component_export.h"
 #include "base/logging.h"
 #include "base/notreached.h"
+#include "base/observer_list_types.h"
 #include "google_apis/gaia/gaia_auth_consumer.h"
 #include "google_apis/gaia/google_service_auth_error.h"
 #include "net/base/net_errors.h"
@@ -128,9 +129,10 @@ enum SuccessReason {
 // An interface that defines the callbacks for objects that the
 // Authenticator class will call to report the success/failure of
 // authentication for Chromium OS.
-class COMPONENT_EXPORT(CHROMEOS_LOGIN_AUTH) AuthStatusConsumer {
+class COMPONENT_EXPORT(CHROMEOS_LOGIN_AUTH) AuthStatusConsumer
+    : public base::CheckedObserver {
  public:
-  virtual ~AuthStatusConsumer() {}
+  ~AuthStatusConsumer() override = default;
   // The current login attempt has ended in failure, with error |error|.
   virtual void OnAuthFailure(const AuthFailure& error) = 0;