Fix how Save-Page-As responds to web requests blocked by extensions.

content/browser/download/save_package.cc

Index: content/browser/download/save_package.cc
diff --git a/content/browser/download/save_package.cc b/content/browser/download/save_package.cc
index 5b7d6a6ead1e1e160d6999fc193f791e2fc2b738..6e46f8266222a2942419bf2151046b2436e5540a 100644
--- a/content/browser/download/save_package.cc
+++ b/content/browser/download/save_package.cc
@@ -1009,7 +1009,14 @@ void SavePackage::GetSerializedHtmlWithLocalLinksForFrame(
       target_frame_tree_node_id);
   if (it != frame_tree_node_id_to_contained_save_items_.end()) {
     for (SaveItem* save_item : it->second) {
-      DCHECK(save_item->has_final_name());
+      // Skip items that failed to save.
+      if (!save_item->has_final_name()) {
+        DCHECK_EQ(SaveItem::SaveState::COMPLETE, save_item->state());
+        DCHECK(!save_item->success());
+        continue;
+      }
+
+      // Calculate the relative path for referring to the |save_item|.
       base::FilePath local_path(base::FilePath::kCurrentDirectory);
       if (target_tree_node->IsMainFrame()) {
         local_path = local_path.Append(saved_main_directory_path_.BaseName());