Add DidSaveScrollOrScaleState flag to prevent restoreScrollPositionAndViewState restore from default

content/renderer/history_serialization.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 "content/renderer/history_serialization.h"
 
 #include <stddef.h>
 
 #include "base/strings/nullable_string16.h"
 #include "content/child/web_url_request_util.h"
@@ skipping 36 matching lines @@
     state->state_object =
         WebString::toNullableString16(item.stateObject().toString());
   }
   state->scroll_restoration_type = item.scrollRestorationType();
   state->visual_viewport_scroll_offset = item.visualViewportScrollOffset();
   state->scroll_offset = item.getScrollOffset();
   state->item_sequence_number = item.itemSequenceNumber();
   state->document_sequence_number =
       item.documentSequenceNumber();
   state->page_scale_factor = item.pageScaleFactor();
+  state->did_save_scroll_or_scale_state = item.didSaveScrollOrScaleState();
   ToNullableString16Vector(item.getDocumentState(), &state->document_state);
 
   state->http_body.http_content_type =
       WebString::toNullableString16(item.httpContentType());
   const WebHTTPBody& http_body = item.httpBody();
   if (!http_body.isNull()) {
     state->http_body.request_body = GetRequestBodyForWebHTTPBody(http_body);
     state->http_body.contains_passwords = http_body.containsPasswordData();
   }
 }
@@ skipping 28 matching lines @@
   WebVector<WebString> document_state(state.document_state.size());
   std::transform(state.document_state.begin(), state.document_state.end(),
                  document_state.begin(), [](const base::NullableString16& s) {
                    return WebString::fromUTF16(s);
                  });
   item.setDocumentState(document_state);
   item.setScrollRestorationType(state.scroll_restoration_type);
   item.setVisualViewportScrollOffset(state.visual_viewport_scroll_offset);
   item.setScrollOffset(state.scroll_offset);
   item.setPageScaleFactor(state.page_scale_factor);
+  item.setDidSaveScrollOrScaleState(state.did_save_scroll_or_scale_state);
 
   // These values are generated at WebHistoryItem construction time, and we
   // only want to override those new values with old values if the old values
   // are defined.  A value of 0 means undefined in this context.
   if (state.item_sequence_number)
     item.setItemSequenceNumber(state.item_sequence_number);
   if (state.document_sequence_number)
     item.setDocumentSequenceNumber(state.document_sequence_number);
 
   item.setHTTPContentType(
@@ skipping 37 matching lines @@
   if (!DecodePageState(page_state.ToEncodedData(), &state))
     return std::unique_ptr<HistoryEntry>();
 
   std::unique_ptr<HistoryEntry> entry(new HistoryEntry());
   RecursivelyGenerateHistoryItem(state.top, entry->root_history_node());
 
   return entry;
 }
 
 }  // namespace content