Changing scroll and view state in onpopstate shouldn't overwrite back/forward state restore

third_party/WebKit/Source/core/loader/DocumentLoader.cpp

 /*
  * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 336 matching lines @@
   // Don't propagate state from the old item if this is a different-document
   // navigation, unless the before and after pages are logically related. This
   // means they have the same url (ignoring fragment) and the new item was
   // loaded via reload or client redirect.
   HistoryCommitType history_commit_type = LoadTypeToCommitType(load_type);
   if (navigation_type == HistoryNavigationType::kDifferentDocument &&
       (history_commit_type != kHistoryInertCommit ||
        !EqualIgnoringFragmentIdentifier(old_item->Url(), history_item_->Url())))
     return;
   history_item_->SetDocumentSequenceNumber(old_item->DocumentSequenceNumber());
-  history_item_->SetScrollOffset(old_item->GetScrollOffset());
-  history_item_->SetDidSaveScrollOrScaleState(
-      old_item->DidSaveScrollOrScaleState());
-  history_item_->SetVisualViewportScrollOffset(
-      old_item->VisualViewportScrollOffset());
-  history_item_->SetPageScaleFactor(old_item->PageScaleFactor());
+
+  if (HistoryItem::ScrollAndViewState* scroll_and_scale_state =

[majidvp, 2017/06/26 16:19:26]

s/scroll_and_scale_state/scroll_and_view_state/

Instead of copying each member individually this should just copy the old
object, either via a copy constructor or just use of|CopyScrollAndViewState()|.

[Nate Chapin, 2017/07/11 22:17:59]

Done.

+          old_item->GetScrollAndViewState()) {
+    history_item_->SetScrollOffset(scroll_and_scale_state->scroll_offset_);
+    history_item_->SetVisualViewportScrollOffset(
+        scroll_and_scale_state->visual_viewport_scroll_offset_);
+    history_item_->SetPageScaleFactor(
+        scroll_and_scale_state->page_scale_factor_);
+  }
+
   history_item_->SetScrollRestorationType(old_item->ScrollRestorationType());
 
   // The item sequence number determines whether items are "the same", such
   // back/forward navigation between items with the same item sequence number is
   // a no-op. Only treat this as identical if the navigation did not create a
   // back/forward entry and the url is identical or it was loaded via
   // history.replaceState().
   if (history_commit_type == kHistoryInertCommit &&
       (navigation_type == HistoryNavigationType::kHistoryApi ||
        old_item->Url() == history_item_->Url())) {
@@ skipping 717 matching lines @@
                      InstallNewDocumentReason::kJavascriptURL,
                      kForceSynchronousParsing, KURL());
   if (!source.IsNull())
     writer_->AppendReplacingData(source);
   EndWriting();
 }
 
 DEFINE_WEAK_IDENTIFIER_MAP(DocumentLoader);
 
 }  // namespace blink