Get signals working in the EXTRA_DATA section of MHTML

components/offline_pages/core/offline_page_model_impl.cc

Index: components/offline_pages/core/offline_page_model_impl.cc
diff --git a/components/offline_pages/core/offline_page_model_impl.cc b/components/offline_pages/core/offline_page_model_impl.cc
index 2e87035d1f69577f80997550ca96de221c845d67..0dc5e3d2fc0e881d99e076800e29f036044228b0 100644
--- a/components/offline_pages/core/offline_page_model_impl.cc
+++ b/components/offline_pages/core/offline_page_model_impl.cc
@@ -338,6 +338,7 @@ void OfflinePageModelImpl::RemoveObserver(Observer* observer) {
 void OfflinePageModelImpl::SavePage(
     const SavePageParams& save_page_params,
     std::unique_ptr<OfflinePageArchiver> archiver,
+    const std::string& signal_data,
     const SavePageCallback& callback) {
   DCHECK(is_loaded_);
 
@@ -366,7 +367,7 @@ void OfflinePageModelImpl::SavePage(
   // popup overlay that obstructs viewing the normal content.
   create_archive_params.remove_popup_overlay = save_page_params.is_background;
   archiver->CreateArchive(
-      archives_dir_, create_archive_params,
+      archives_dir_, create_archive_params, signal_data,
       base::Bind(&OfflinePageModelImpl::OnCreateArchiveDone,
                  weak_ptr_factory_.GetWeakPtr(), save_page_params, offline_id,
                  GetCurrentTime(), callback));