Better remove HistoryNodes

content/renderer/history_serialization.cc

Index: content/renderer/history_serialization.cc
diff --git a/content/renderer/history_serialization.cc b/content/renderer/history_serialization.cc
index 1d14357f5a612e16fc410f0a08fa0d5d3ec5c65d..5dd704cef1eee3de093588df3db813c0b29a3d8a 100644
--- a/content/renderer/history_serialization.cc
+++ b/content/renderer/history_serialization.cc
@@ -95,8 +95,6 @@ void GenerateFrameStateFromItem(const WebHistoryItem& item,
   state->item_sequence_number = item.itemSequenceNumber();
   state->document_sequence_number =
       item.documentSequenceNumber();
-  state->frame_sequence_number =
-      item.frameSequenceNumber();
   state->page_scale_factor = item.pageScaleFactor();
   ToNullableString16Vector(item.documentState(), &state->document_state);
 
@@ -155,8 +153,6 @@ void RecursivelyGenerateHistoryItem(const ExplodedFrameState& state,
     item.setItemSequenceNumber(state.item_sequence_number);
   if (state.document_sequence_number)
     item.setDocumentSequenceNumber(state.document_sequence_number);
-  if (state.frame_sequence_number)
-    item.setFrameSequenceNumber(state.frame_sequence_number);
 
   item.setHTTPContentType(state.http_body.http_content_type);
   if (!state.http_body.is_null) {