Split the frame tree logic out of HistoryItem

Source/web/WebFrameImpl.cpp

Index: Source/web/WebFrameImpl.cpp
diff --git a/Source/web/WebFrameImpl.cpp b/Source/web/WebFrameImpl.cpp
index 59e09e5bf1e1aa298b0ce98c6c8024aafe3398fd..71d8ec43d316b9a433b802c7129cbf33e8ff1b43 100644
--- a/Source/web/WebFrameImpl.cpp
+++ b/Source/web/WebFrameImpl.cpp
@@ -926,8 +926,7 @@ void WebFrameImpl::loadHistoryItem(const WebHistoryItem& item)
     ASSERT(historyItem);
 
     frame()->loader().prepareForHistoryNavigation();
-    RefPtr<HistoryItem> currentItem = frame()->loader().history()->currentItem();
-    m_inSameDocumentHistoryLoad = currentItem && currentItem->shouldDoSameDocumentNavigationTo(historyItem.get());
+    m_inSameDocumentHistoryLoad = frame()->loader().history()->shouldPerformSameDocumentHistoryNavigation(frame(), historyItem.get());
     frame()->page()->goToItem(historyItem.get());
     m_inSameDocumentHistoryLoad = false;
 }
@@ -1000,7 +999,7 @@ WebHistoryItem WebFrameImpl::previousHistoryItem() const
     // only get saved to history when it becomes the previous item.  The caller
     // is expected to query the history item after a navigation occurs, after
     // the desired history item has become the previous entry.
-    return WebHistoryItem(frame()->loader().history()->previousItem());
+    return WebHistoryItem(frame()->loader().history()->previousItemForExport(frame()));
 }
 
 WebHistoryItem WebFrameImpl::currentHistoryItem() const
@@ -1018,11 +1017,11 @@ WebHistoryItem WebFrameImpl::currentHistoryItem() const
     // clobbering here?
     if (!m_inSameDocumentHistoryLoad && (frame()->loader().loadType() == FrameLoadTypeStandard
         || !frame()->loader().activeDocumentLoader()->isLoadingInAPISense()))
-        frame()->loader().history()->saveDocumentAndScrollState();
+        frame()->loader().history()->saveDocumentAndScrollState(frame());
 
-    if (HistoryItem* item = frame()->loader().history()->provisionalItem())
+    if (RefPtr<HistoryItem> item = frame()->loader().history()->provisionalItemForExport(frame()))
         return WebHistoryItem(item);
-    return WebHistoryItem(frame()->page()->mainFrame()->loader().history()->currentItem());
+    return WebHistoryItem(frame()->loader().history()->currentItemForExport(frame()));
 }
 
 void WebFrameImpl::enableViewSourceMode(bool enable)
@@ -2198,12 +2197,11 @@ PassRefPtr<Frame> WebFrameImpl::createChildFrame(const FrameLoadRequest& request
     if (!childFrame->tree().parent())
         return 0;
 
-    HistoryItem* parentItem = frame()->loader().history()->currentItem();
     HistoryItem* childItem = 0;
     // If we're moving in the back/forward list, we might want to replace the content
     // of this child frame with whatever was there at that point.
-    if (parentItem && parentItem->children().size() && isBackForwardLoadType(frame()->loader().loadType()) && !frame()->document()->loadEventFinished())
-        childItem = parentItem->childItemWithTarget(childFrame->tree().uniqueName());
+    if (isBackForwardLoadType(frame()->loader().loadType()) && !frame()->document()->loadEventFinished())
+        childItem = frame()->loader().history()->currentItem(childFrame.get());
 
     if (childItem)
         childFrame->loader().loadHistoryItem(childItem);