Split the frame tree logic out of HistoryItem

Source/core/history/HistoryItem.h

Index: Source/core/history/HistoryItem.h
diff --git a/Source/core/history/HistoryItem.h b/Source/core/history/HistoryItem.h
index 15793db5257715c5c1aefb330499eba38d72e469..042fadda8f006af7e0284e95e0bfdb5b23fd0aa0 100644
--- a/Source/core/history/HistoryItem.h
+++ b/Source/core/history/HistoryItem.h
@@ -85,7 +85,6 @@ public:
     void setStateObject(PassRefPtr<SerializedScriptValue> object);
     SerializedScriptValue* stateObject() const { return m_stateObject.get(); }
 
-    void setItemSequenceNumber(long long number) { m_itemSequenceNumber = number; }
     long long itemSequenceNumber() const { return m_itemSequenceNumber; }
 
     void setDocumentSequenceNumber(long long number) { m_documentSequenceNumber = number; }
@@ -96,28 +95,15 @@ public:
     void setFormContentType(const String&);
 
     void addChildItem(PassRefPtr<HistoryItem>);
-    void setChildItem(PassRefPtr<HistoryItem>);
-    HistoryItem* childItemWithTarget(const String&) const;
-    HistoryItem* childItemWithDocumentSequenceNumber(long long number) const;
     const HistoryItemVector& children() const;
     void clearChildren();
 
-    bool shouldDoSameDocumentNavigationTo(HistoryItem* otherItem) const;
-    bool hasSameFrames(HistoryItem* otherItem) const;
-
     bool isCurrentDocument(Document*) const;
 
-#ifndef NDEBUG
-    int showTree() const;
-    int showTreeWithIndent(unsigned indentLevel) const;
-#endif
-
 private:
     HistoryItem();
     explicit HistoryItem(const HistoryItem&);
 
-    bool hasSameDocumentTree(HistoryItem* otherItem) const;
-
     String m_urlString;
     String m_originalURLString;
     String m_referrer;
@@ -151,9 +137,4 @@ private:
 
 } //namespace WebCore
 
-#ifndef NDEBUG
-// Outside the WebCore namespace for ease of invocation from gdb.
-extern "C" int showTree(const WebCore::HistoryItem*);
-#endif
-
 #endif // HISTORYITEM_H