Split the frame tree logic out of HistoryItem

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 379295491ea1a7649d7b43bcb439e46f34765312..343f5b4653b892f0b052098ffc219999a160db4a 100644
--- a/Source/core/loader/FrameLoader.h
+++ b/Source/core/loader/FrameLoader.h
@@ -82,16 +82,12 @@ public:
 
     Frame* frame() const { return m_frame; }
 
-    HistoryController* history() const { return &m_history; }
-
     MixedContentChecker* mixedContentChecker() const { return &m_mixedContentChecker; }
 
-    void prepareForHistoryNavigation();
-
     // These functions start a load. All eventually call into loadWithNavigationAction() or loadInSameDocument().
     void load(const FrameLoadRequest&); // The entry point for non-reload, non-history loads.
     void reload(ReloadPolicy = NormalReload, const KURL& overrideURL = KURL(), const String& overrideEncoding = String());
-    void loadHistoryItem(HistoryItem*); // The entry point for all back/forward loads
+    void loadHistoryItem(HistoryItem*, HistoryLoadType = HistoryDifferentDocumentLoad); // The entry point for all back/forward loads
 
     static void reportLocalLoadFailed(Frame*, const String& url);
 
@@ -134,6 +130,7 @@ public:
 
     bool subframeIsLoading() const;
 
+    bool shouldTreatURLAsSameAsCurrent(const KURL&) const;
     bool shouldTreatURLAsSrcdocDocument(const KURL&) const;
 
     FrameLoadType loadType() const;
@@ -209,6 +206,8 @@ public:
     void updateForSameDocumentNavigation(const KURL&, SameDocumentNavigationSource, PassRefPtr<SerializedScriptValue>, UpdateBackForwardListPolicy);
 
 private:
+    HistoryController* history() const;
+
     bool allChildrenAreComplete() const; // immediate children, not all descendants
 
     void completed();
@@ -216,8 +215,6 @@ private:
     void checkTimerFired(Timer<FrameLoader>*);
     void didAccessInitialDocumentTimerFired(Timer<FrameLoader>*);
 
-    void insertDummyHistoryItem();
-
     bool prepareRequestForThisFrame(FrameLoadRequest&);
     void setReferrerForFrameRequest(ResourceRequest&, ShouldSendReferrer);
     FrameLoadType determineFrameLoadType(const FrameLoadRequest&);
@@ -246,15 +243,12 @@ private:
     void scheduleCheckCompleted();
     void startCheckCompleteTimer();
 
-    bool shouldTreatURLAsSameAsCurrent(const KURL&) const;
-
     Frame* m_frame;
     FrameLoaderClient* m_client;
 
     // FIXME: These should be OwnPtr<T> to reduce build times and simplify
     // header dependencies unless performance testing proves otherwise.
     // Some of these could be lazily created for memory savings on devices.
-    mutable HistoryController m_history;
     mutable FrameLoaderStateMachine m_stateMachine;
     mutable MixedContentChecker m_mixedContentChecker;