Persist offline page info in a navigation entry if needed

components/sessions/content/content_serialized_navigation_driver.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_SESSIONS_CONTENT_CONTENT_SERIALIZED_NAVIGATION_DRIVER_H_
 #define COMPONENTS_SESSIONS_CONTENT_CONTENT_SERIALIZED_NAVIGATION_DRIVER_H_
 
 #include "components/sessions/core/serialized_navigation_driver.h"
 
 #include "components/sessions/core/sessions_export.h"
@@ skipping 19 matching lines @@
   int GetDefaultReferrerPolicy() const override;
   bool MapReferrerPolicyToOldValues(int referrer_policy,
                                     int* mapped_referrer_policy) const override;
   bool MapReferrerPolicyToNewValues(int referrer_policy,
                                     int* mapped_referrer_policy) const override;
   std::string GetSanitizedPageStateForPickle(
       const SerializedNavigationEntry* navigation) const override;
   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:
   ContentSerializedNavigationDriver();
   friend struct base::DefaultSingletonTraits<ContentSerializedNavigationDriver>;
+
+  ExtendedInfoHandlerMap extended_info_handler_map_;
 };
 
 }  // namespace sessions
 
 #endif  // COMPONENTS_SESSIONS_CONTENT_CONTENT_SERIALIZED_NAVIGATION_DRIVER_H_