Split the frame tree logic out of HistoryItem

Source/core/page/Page.h

Index: Source/core/page/Page.h
diff --git a/Source/core/page/Page.h b/Source/core/page/Page.h
index 9f3e9a639a13648dee022acb20852bfc26943d1a..fa579d8a42a275c2f50ab891fb037111441d9dbe 100644
--- a/Source/core/page/Page.h
+++ b/Source/core/page/Page.h
@@ -52,6 +52,7 @@ class FocusController;
 class Frame;
 class FrameSelection;
 class HaltablePlugin;
+class HistoryController;
 class HistoryItem;
 class InspectorClient;
 class InspectorController;
@@ -112,6 +113,8 @@ public:
 
     EditorClient& editorClient() const { return *m_editorClient; }
 
+    HistoryController* history() const { return m_history.get(); }
+
     void setMainFrame(PassRefPtr<Frame>);
     Frame* mainFrame() const { return m_mainFrame.get(); }
 
@@ -120,9 +123,6 @@ public:
     bool openedByDOM() const;
     void setOpenedByDOM();
 
-    // DEPRECATED. Use backForward() instead of the following function.
-    void goToItem(HistoryItem*);
-
     enum PageGroupType { PrivatePageGroup, SharedPageGroup };
     void setGroupType(PageGroupType);
     void clearPageGroup();
@@ -251,6 +251,7 @@ private:
     const OwnPtr<PointerLockController> m_pointerLockController;
     RefPtr<ScrollingCoordinator> m_scrollingCoordinator;
 
+    const OwnPtr<HistoryController> m_history;
     const OwnPtr<Settings> m_settings;
     const OwnPtr<ProgressTracker> m_progress;