Don't reuse HistoryItems for multiple navigations

Source/core/loader/HistoryItem.cpp

Index: Source/core/loader/HistoryItem.cpp
diff --git a/Source/core/loader/HistoryItem.cpp b/Source/core/loader/HistoryItem.cpp
index 4c531794721025c06eff61b1d2b07128af1d4a7c..0672020f96939868681f8ed86546662726fd731c 100644
--- a/Source/core/loader/HistoryItem.cpp
+++ b/Source/core/loader/HistoryItem.cpp
@@ -56,16 +56,6 @@ HistoryItem::~HistoryItem()
 {
 }
 
-void HistoryItem::generateNewItemSequenceNumber()
-{
-    m_itemSequenceNumber = generateSequenceNumber();
-}
-
-void HistoryItem::generateNewDocumentSequenceNumber()
-{
-    m_documentSequenceNumber = generateSequenceNumber();
-}
-
 const String& HistoryItem::urlString() const
 {
     return m_urlString;
@@ -128,12 +118,6 @@ void HistoryItem::setScrollPoint(const IntPoint& point)
     m_scrollPoint = point;
 }
 
-void HistoryItem::clearScrollPoint()
-{
-    m_scrollPoint = IntPoint();
-    m_pinchViewportScrollPoint = FloatPoint();
-}
-
 float HistoryItem::pageScaleFactor() const
 {
     return m_pageScaleFactor;