[ios] Clean how WebUsageEnabled flag is restored for WebStateList.

ios/chrome/browser/web_state_list/web_state_list_serialization.mm

Index: ios/chrome/browser/web_state_list/web_state_list_serialization.mm
diff --git a/ios/chrome/browser/web_state_list/web_state_list_serialization.mm b/ios/chrome/browser/web_state_list/web_state_list_serialization.mm
index 756935f31cdb91bf00eee571c1c913476e73539e..f104d3a575f0ddbb865064e1a987a6cbb0affce5 100644
--- a/ios/chrome/browser/web_state_list/web_state_list_serialization.mm
+++ b/ios/chrome/browser/web_state_list/web_state_list_serialization.mm
@@ -171,12 +171,10 @@ SessionWindowIOS* SerializeWebStateList(WebStateList* web_state_list) {
 
 void DeserializeWebStateList(WebStateList* web_state_list,
                              SessionWindowIOS* session_window,
-                             bool web_usage_enabled,
                              const WebStateFactory& web_state_factory) {
   int old_count = web_state_list->count();
   for (CRWSessionStorage* session in session_window.sessions) {
     std::unique_ptr<web::WebState> web_state = web_state_factory.Run(session);
-    web_state->SetWebUsageEnabled(web_usage_enabled);
     web_state_list->InsertWebState(web_state_list->count(),
                                    std::move(web_state));
   }