Don't reuse HistoryItems for multiple navigations

Source/core/loader/FrameLoader.h

Index: Source/core/loader/FrameLoader.h
diff --git a/Source/core/loader/FrameLoader.h b/Source/core/loader/FrameLoader.h
index 1cabfeb76d65cfc24a2fda9f914fd112d90a5c9c..9fb261c98258874664bf594a1dbed90d3489f1c9 100644
--- a/Source/core/loader/FrameLoader.h
+++ b/Source/core/loader/FrameLoader.h
@@ -171,7 +171,6 @@ public:
 
     HistoryItem* currentItem() const { return m_currentItem.get(); }
     void saveScrollState();
-    void clearScrollPositionAndViewState();
 
     void restoreScrollPositionAndViewState();
 
@@ -192,8 +191,7 @@ private:
 
     void startLoad(FrameLoadRequest&, FrameLoadType, NavigationPolicy);
 
-
-    void setHistoryItemStateForCommit(HistoryCommitType, bool isPushOrReplaceState = false, HistoryScrollRestorationType = ScrollRestorationAuto, PassRefPtr<SerializedScriptValue> = nullptr);
+    void setHistoryItemStateForCommit(HistoryCommitType, bool isSameDocument, bool isPushOrReplaceState = false);
 
     void loadInSameDocument(const KURL&, PassRefPtr<SerializedScriptValue> stateObject, FrameLoadType, ClientRedirectPolicy);