Remove FOR_EACH_OBSERVER from arc/ since it's being deprecated

components/arc/intent_helper/link_handler_model_impl.cc

Index: components/arc/intent_helper/link_handler_model_impl.cc
diff --git a/components/arc/intent_helper/link_handler_model_impl.cc b/components/arc/intent_helper/link_handler_model_impl.cc
index 4c6f7382f6a040223c8564f5769edbe1dbd2cbf2..c20d20633ca170fb1094ccae1bcba2302d76a6a5 100644
--- a/components/arc/intent_helper/link_handler_model_impl.cc
+++ b/components/arc/intent_helper/link_handler_model_impl.cc
@@ -132,7 +132,8 @@ void LinkHandlerModelImpl::NotifyObserver(
     ash::LinkHandlerInfo handler = {handlers_[i]->name.get(), icon, i};
     handlers.push_back(handler);
   }
-  FOR_EACH_OBSERVER(Observer, observer_list_, ModelChanged(handlers));
+  for (auto& observer : observer_list_)
+    observer.ModelChanged(handlers);
 }
 
 // static