Persist offline page info in a navigation entry if needed

components/sessions/ios/ios_serialized_navigation_driver.h

Index: components/sessions/ios/ios_serialized_navigation_driver.h
diff --git a/components/sessions/ios/ios_serialized_navigation_driver.h b/components/sessions/ios/ios_serialized_navigation_driver.h
index 7982ad3145e794307c2f5100a09e04e9f01e9666..5ea283ac8006fb068e60ec45c98d630b7ac1aa06 100644
--- a/components/sessions/ios/ios_serialized_navigation_driver.h
+++ b/components/sessions/ios/ios_serialized_navigation_driver.h
@@ -5,6 +5,7 @@
 #ifndef COMPONENTS_SESSIONS_IOS_IOS_SERIALIZED_NAVIGATION_DRIVER_H_
 #define COMPONENTS_SESSIONS_IOS_IOS_SERIALIZED_NAVIGATION_DRIVER_H_
 
+#include "components/sessions/content/extended_info_handler.h"
 #include "components/sessions/core/serialized_navigation_driver.h"
 
 namespace base {
@@ -35,10 +36,16 @@ class IOSSerializedNavigationDriver
   void Sanitize(SerializedNavigationEntry* navigation) const override;
   std::string StripReferrerFromPageState(
       const std::string& page_state) const override;
+  void RegisterExtendedInfoHandler(
+      const std::string& key,
+      std::unique_ptr<ExtendedInfoHandler> handler) override;
+  const ExtendedInfoHandlerMap& GetAllExtendedInfoHandlers() const override;
 
  private:
   IOSSerializedNavigationDriver();
   friend struct base::DefaultSingletonTraits<IOSSerializedNavigationDriver>;
+
+  ExtendedInfoHandlerMap extended_info_handler_map_;
 };
 
 }  // namespace sessions