cros: Update ash when prefs related to lock are changed

chrome/browser/ui/ash/session_controller_client.h

Index: chrome/browser/ui/ash/session_controller_client.h
diff --git a/chrome/browser/ui/ash/session_controller_client.h b/chrome/browser/ui/ash/session_controller_client.h
index 9fffbe0a47eac7d325d190d37d70297a51780446..a7e4dc4cd8e32392190d1d8ac103d21c5f7ee346 100644
--- a/chrome/browser/ui/ash/session_controller_client.h
+++ b/chrome/browser/ui/ash/session_controller_client.h
@@ -5,6 +5,8 @@
 #ifndef CHROME_BROWSER_UI_ASH_SESSION_CONTROLLER_CLIENT_H_
 #define CHROME_BROWSER_UI_ASH_SESSION_CONTROLLER_CLIENT_H_
 
+#include <vector>
+
 #include "ash/public/interfaces/session_controller.mojom.h"
 #include "base/callback_forward.h"
 #include "base/gtest_prod_util.h"
@@ -18,6 +20,7 @@
 #include "mojo/public/cpp/bindings/binding.h"
 
 class Profile;
+class PrefChangeRegistrar;
 
 namespace ash {
 enum class AddUserSessionPolicy;
@@ -97,6 +100,7 @@ class SessionControllerClient
  private:
   FRIEND_TEST_ALL_PREFIXES(SessionControllerClientTest, SendUserSession);
   FRIEND_TEST_ALL_PREFIXES(SessionControllerClientTest, SupervisedUser);
+  FRIEND_TEST_ALL_PREFIXES(SessionControllerClientTest, UserPrefsChange);
 
   // Called when the login profile is ready.
   void OnLoginUserProfilePrepared(Profile* profile);
@@ -131,6 +135,11 @@ class SessionControllerClient
 
   content::NotificationRegistrar registrar_;
 
+  // Pref change observers to update session info when a relevant user pref
+  // changes. There is one observer per user and they have no particular order,
+  // i.e. they don't much the user session order.
+  std::vector<std::unique_ptr<PrefChangeRegistrar>> pref_change_registrars_;
+
   // Used to suppress duplicate IPCs to ash.
   ash::mojom::SessionInfoPtr last_sent_session_info_;
   ash::mojom::UserSessionPtr last_sent_user_session_;