Oilpan: move a page's UndoStack to the heap.

Source/core/page/Page.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 239 matching lines @@
     PageAnimator m_animator;
     const OwnPtr<AutoscrollController> m_autoscrollController;
     const OwnPtr<Chrome> m_chrome;
     const OwnPtrWillBeMember<DragCaretController> m_dragCaretController;
     const OwnPtrWillBeMember<DragController> m_dragController;
     const OwnPtr<FocusController> m_focusController;
     const OwnPtr<ContextMenuController> m_contextMenuController;
     const OwnPtr<InspectorController> m_inspectorController;
     const OwnPtrWillBeMember<PointerLockController> m_pointerLockController;
     OwnPtr<ScrollingCoordinator> m_scrollingCoordinator;
-    const OwnPtr<UndoStack> m_undoStack;
+    const OwnPtrWillBeMember<UndoStack> m_undoStack;
 
     RefPtr<Frame> m_mainFrame;
 
     mutable RefPtr<PluginData> m_pluginData;
 
     BackForwardClient* m_backForwardClient;
     EditorClient* const m_editorClient;
     SpellCheckerClient* const m_spellCheckerClient;
     StorageClient* m_storageClient;
     OwnPtrWillBeMember<ValidationMessageClient> m_validationMessageClient;
@@ skipping 23 matching lines @@
     WillBeHeapHashSet<RawPtrWillBeWeakMember<MultisamplingChangedObserver> > m_multisamplingChangedObservers;
 
     // A pointer to all the interfaces provided to in-process Frames for this Page.
     // FIXME: Most of the members of Page should move onto FrameHost.
     OwnPtrWillBeMember<FrameHost> m_frameHost;
 };
 
 } // namespace WebCore
 
 #endif // Page_h