Persist offline page info in a navigation entry if needed

components/sessions/content/content_serialized_navigation_driver.cc

 // 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.
 
 #include "components/sessions/content/content_serialized_navigation_driver.h"
 
 #include "base/memory/singleton.h"
 #include "build/build_config.h"
+#include "components/sessions/content/extended_info_handler.h"
 #include "components/sessions/core/serialized_navigation_entry.h"
 #include "content/public/common/page_state.h"
 #include "content/public/common/referrer.h"
 #include "content/public/common/url_constants.h"
 
 namespace sessions {
 
 namespace {
 const int kObsoleteReferrerPolicyAlways = 0;
 const int kObsoleteReferrerPolicyDefault = 1;
@@ skipping 107 matching lines @@
 #endif  // defined(OS_ANDROID)
 }
 
 std::string ContentSerializedNavigationDriver::StripReferrerFromPageState(
       const std::string& page_state) const {
   return content::PageState::CreateFromEncodedData(page_state)
       .RemoveReferrer()
       .ToEncodedData();
 }
 
+void ContentSerializedNavigationDriver::RegisterExtendedInfoHandler(
+    const std::string& key,
+    std::unique_ptr<ExtendedInfoHandler> handler) {
+  DCHECK(!key.empty());

[sky, 2016/09/29 03:08:19]

Please also add a DCHECK that there isn't a handler registered for key already
and that handler.get() is non-null.

[jianli, 2016/09/29 22:02:29]

Done.

+  extended_info_handler_map_[key] = std::move(handler);
+}
+
+const ContentSerializedNavigationDriver::ExtendedInfoHandlerMap&
+ContentSerializedNavigationDriver::GetAllExtendedInfoHandlers() const {
+  return extended_info_handler_map_;
+}
+
 }  // namespace sessions