Persist offline page info in a navigation entry if needed

components/sessions/content/content_serialized_navigation_driver.cc

Index: components/sessions/content/content_serialized_navigation_driver.cc
diff --git a/components/sessions/content/content_serialized_navigation_driver.cc b/components/sessions/content/content_serialized_navigation_driver.cc
index a3305a8695311157429112f3677d91fa124daac5..734f09b6b84c6672b724ac1f7f9fb49ca4a72f69 100644
--- a/components/sessions/content/content_serialized_navigation_driver.cc
+++ b/components/sessions/content/content_serialized_navigation_driver.cc
@@ -133,4 +133,18 @@ std::string ContentSerializedNavigationDriver::StripReferrerFromPageState(
       .ToEncodedData();
 }
 
+void ContentSerializedNavigationDriver::RegisterExtendedInfoHandler(
+    const std::string& key,
+    std::unique_ptr<ExtendedInfoHandler> handler) {
+  DCHECK(!key.empty());
+  DCHECK(!extended_info_handler_map_.count(key));
+  DCHECK(handler.get());
+  extended_info_handler_map_[key] = std::move(handler);
+}
+
+const ContentSerializedNavigationDriver::ExtendedInfoHandlerMap&
+ContentSerializedNavigationDriver::GetAllExtendedInfoHandlers() const {
+  return extended_info_handler_map_;
+}
+
 }  // namespace sessions