cros: HTML fixes needed to reinitializing an existing lock WebUI.

chrome/browser/chromeos/login/signin_screen_controller.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_LOGIN_SIGNIN_SCREEN_CONTROLLER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_SIGNIN_SCREEN_CONTROLLER_H_
 
 #include "base/macros.h"
 #include "chrome/browser/chromeos/login/screens/gaia_screen.h"
 #include "chrome/browser/chromeos/login/screens/user_selection_screen.h"
 #include "chrome/browser/chromeos/login/ui/login_display_host.h"
 #include "components/user_manager/remove_user_delegate.h"
 #include "components/user_manager/user.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
 class AccountId;
 
 namespace chromeos {
 
 class LoginDisplayWebUIHandler;
 class OobeUI;
 
 // Class that manages control flow between wizard screens. Wizard controller
 // interacts with screen controllers to move the user between screens.
+//
+// This class is allocated when the signin or lock screen is actually visible to
+// the user. It is a 'per-session' class; SignInScreenHandler, in comparsion, is
+// tied to the WebContents lifetime and therefore may live beyond this class.
 class SignInScreenController : public user_manager::RemoveUserDelegate,
                                public content::NotificationObserver {
  public:
   SignInScreenController(OobeUI* oobe_ui,
                          LoginDisplay::Delegate* login_display_delegate);
   ~SignInScreenController() override;
 
   // Returns the default wizard controller if it has been created.
   static SignInScreenController* Get() { return instance_; }
 
@@ skipping 38 matching lines @@
 
   // Used for notifications during the login process.
   content::NotificationRegistrar registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(SignInScreenController);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_SIGNIN_SCREEN_CONTROLLER_H_