Move HistoryItem handling to DocumentLoader

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

Index: third_party/WebKit/Source/core/dom/Document.cpp
diff --git a/third_party/WebKit/Source/core/dom/Document.cpp b/third_party/WebKit/Source/core/dom/Document.cpp
index 4ba216fdc155a192f52295d013dd8ba229258402..88fd97fb0bcc4c731f0b225f5fa112f2cdfbca80 100644
--- a/third_party/WebKit/Source/core/dom/Document.cpp
+++ b/third_party/WebKit/Source/core/dom/Document.cpp
@@ -1632,10 +1632,9 @@ Node::NodeType Document::getNodeType() const {
 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;
 }