Replacing user profile with lockscreen profile.

Using the new lockscreen profile as a browser context for WebUI
displaying SAML page while re-authenticating users on lockscreen.

Bug: 1102942
Change-Id: Ib870ab313cca1b8de83cfdd1e4b52fd489faa82a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2606354Reviewed-by: Denis Kuznetsov [CET] <antrim@chromium.org>
Commit-Queue: Mohammed Abdon <mohammedabdon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#840901}

chrome/browser/ui/webui/chromeos/in_session_password_change/lock_screen_reauth_dialogs.cc

@@ -8,6 +8,8 @@
 
 #include "base/bind.h"
 #include "base/json/json_writer.h"
+#include "chrome/browser/chromeos/profiles/profile_helper.h"
+#include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/webui/chromeos/in_session_password_change/confirm_password_change_handler.h"
 #include "chrome/common/webui_url_constants.h"
 #include "chrome/grit/browser_resources.h"
@@ -68,7 +70,8 @@ void LockScreenStartReauthDialog::Show() {
     return;
   }
   g_dialog = new LockScreenStartReauthDialog();
-  g_dialog->ShowSystemDialog();
+  g_dialog->ShowSystemDialogForBrowserContext(
+      ProfileHelper::GetLockScreenIncognitoProfile());
 }
 
 void LockScreenStartReauthDialog::Dismiss() {

chrome/browser/ui/webui/chromeos/in_session_password_change/lock_screen_start_reauth_ui.cc

@@ -21,7 +21,7 @@ LockScreenStartReauthUI::LockScreenStartReauthUI(content::WebUI* web_ui)
     : ui::WebDialogUI(web_ui) {
   Profile* profile = Profile::FromWebUI(web_ui);
   const user_manager::User* user =
-      ProfileHelper::Get()->GetUserByProfile(profile);
+      user_manager::UserManager::Get()->GetActiveUser();
   std::string email;
   if (user) {
     email = user->GetDisplayEmail();