Adjust the message for Roll-forward update

When roll-forward update happens, adjust the message to
"Update installed, pending restart", as it's more appropriate than the
previous message "Failed to update, error code is 21".

b/382561808

Change-Id: I72a6e31052f3894c53ea1e3344c19b910764a205

chrome/updater/updater_module.cc

@@ -98,17 +98,23 @@ void Observer::OnEvent(Events event, const std::string& id) {
       status = "Status is unknown.";
     } else if (crx_update_item_.state == ComponentState::kUpToDate &&
                updater_configurator_->GetPreviousUpdaterStatus().compare(
-                   updater_status_string_map.find(UpdaterStatus::kUpdated)
-                       ->second) == 0) {
+                   updater_status_string_map[UpdaterStatus::kUpdated]) == 0) {
       status = std::string(
-          updater_status_string_map.find(UpdaterStatus::kUpdated)->second);
+          updater_status_string_map[UpdaterStatus::kUpdated]);
     } else {
       status = std::string(
           updater_status_string_map.find(status_iterator->second)->second);
     }
     if (crx_update_item_.state == ComponentState::kUpdateError) {
-      status +=
-          ", error code is " + std::to_string(crx_update_item_.error_code);
+      // QUICK_ROLL_FORWARD update, adjust the message to "Update installed,
+      // pending restart"
+      if (crx_update_item_.error_code == 21) {
+        status = std::string(
+            updater_status_string_map[UpdaterStatus::kUpdated]);
+      } else {
+        status +=
+            ", error code is " + std::to_string(crx_update_item_.error_code);
+      }
     }
     if (updater_notification_ext_ != nullptr) {
       updater_notification_ext_->UpdaterState(