Move HistoryItem handling to DocumentLoader

third_party/WebKit/Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
@@ skipping 1614 matching lines @@
   return "#document";
 }
 
 Node::NodeType Document::getNodeType() const {
   return kDocumentNode;
 }
 
 FormController& Document::formController() {
   if (!m_formController) {
     m_formController = FormController::create();
-    if (m_frame && m_frame->loader().currentItem() &&
-        m_frame->loader().currentItem()->isCurrentDocument(this))

[Nate Chapin, 2017/03/27 21:02:01]

This is the sole use of isCurrentDocument(), and dates back ~10 years to a time
when there wasn't as strong of a tie between Document and
FrameLoader::m_documentLoader and FrameLoader::m_currentItems. The guarantees
that they were changed simultaneously on commit were much weaker, this isn't
necessary now.

-      m_frame->loader().currentItem()->setDocumentState(
-          m_formController->formElementsState());
+    HistoryItem* historyItem = loader() ? loader()->historyItem() : nullptr;
+    if (historyItem)
+      historyItem->setDocumentState(m_formController->formElementsState());
   }
   return *m_formController;
 }
 
 DocumentState* Document::formElementsState() const {
   if (!m_formController)
     return 0;
   return m_formController->formElementsState();
 }
 
@@ skipping 5001 matching lines @@
 }
 
 void showLiveDocumentInstances() {
   WeakDocumentSet& set = liveDocumentSet();
   fprintf(stderr, "There are %u documents currently alive:\n", set.size());
   for (blink::Document* document : set)
     fprintf(stderr, "- Document %p URL: %s\n", document,
             document->url().getString().utf8().data());
 }
 #endif