Clears GuestModeEnabled and AddPersonEnabled user prefs if MD settings is enabled

chrome/browser/ui/webui/signin/user_manager_screen_handler.cc

Index: chrome/browser/ui/webui/signin/user_manager_screen_handler.cc
diff --git a/chrome/browser/ui/webui/signin/user_manager_screen_handler.cc b/chrome/browser/ui/webui/signin/user_manager_screen_handler.cc
index 420c883cd32e789ea0f1d1e663e7b9a38f406758..68de49ca8efe2ffe6b9e13901c644555f7760422 100644
--- a/chrome/browser/ui/webui/signin/user_manager_screen_handler.cc
+++ b/chrome/browser/ui/webui/signin/user_manager_screen_handler.cc
@@ -10,6 +10,7 @@
 #include <vector>
 
 #include "base/bind.h"
+#include "base/feature_list.h"
 #include "base/location.h"
 #include "base/macros.h"
 #include "base/profiler/scoped_tracker.h"
@@ -42,6 +43,7 @@
 #include "chrome/browser/ui/singleton_tabs.h"
 #include "chrome/browser/ui/user_manager.h"
 #include "chrome/browser/ui/webui/profile_helper.h"
+#include "chrome/common/chrome_features.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/grit/chromium_strings.h"
@@ -52,6 +54,7 @@
 #include "components/signin/core/common/profile_management_switches.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/storage_partition.h"
+#include "content/public/browser/user_metrics.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_ui.h"
 #include "google_apis/gaia/gaia_auth_fetcher.h"
@@ -291,6 +294,24 @@ UserManagerScreenHandler::UserManagerScreenHandler() : weak_ptr_factory_(this) {
   profile_attributes_storage_observer_.reset(
       new UserManagerScreenHandler::ProfileUpdateObserver(
           g_browser_process->profile_manager(), this));
+
+  // TODO(mahmadi): Remove the following once prefs are cleared for everyone.
+  PrefService* service = g_browser_process->local_state();
+  DCHECK(service);
+
+  const PrefService::Preference* guest_mode_enabled_pref =
+      service->FindPreference(prefs::kBrowserGuestModeEnabled);
+  const PrefService::Preference* add_person_enabled_pref =
+      service->FindPreference(prefs::kBrowserAddPersonEnabled);
+
+  if (base::FeatureList::IsEnabled(features::kMaterialDesignSettings) &&
+      (guest_mode_enabled_pref->HasUserSetting() ||
+       add_person_enabled_pref->HasUserSetting())) {
+    service->ClearPref(guest_mode_enabled_pref->name());
+    service->ClearPref(add_person_enabled_pref->name());
+    content::RecordAction(
+        base::UserMetricsAction("UserManager_Cleared_Legacy_User_Prefs"));
+  }
 }
 
 UserManagerScreenHandler::~UserManagerScreenHandler() {