Oilpan: make DocumentFragment a heap allocated object.

Source/core/editing/MoveSelectionCommand.h

Index: Source/core/editing/MoveSelectionCommand.h
diff --git a/Source/core/editing/MoveSelectionCommand.h b/Source/core/editing/MoveSelectionCommand.h
index 746c145bf60f684b546679f5c3c6331d5a00e523..60a06b34b5f95cb7661b3e4c02c0e00dfbb85e13 100644
--- a/Source/core/editing/MoveSelectionCommand.h
+++ b/Source/core/editing/MoveSelectionCommand.h
@@ -34,18 +34,18 @@ class DocumentFragment;
 
 class MoveSelectionCommand FINAL : public CompositeEditCommand {
 public:
-    static PassRefPtr<MoveSelectionCommand> create(PassRefPtr<DocumentFragment> fragment, const Position& position, bool smartInsert = false, bool smartDelete = false)
+    static PassRefPtr<MoveSelectionCommand> create(PassRefPtrWillBeRawPtr<DocumentFragment> fragment, const Position& position, bool smartInsert = false, bool smartDelete = false)
     {
         return adoptRef(new MoveSelectionCommand(fragment, position, smartInsert, smartDelete));
     }
 
 private:
-    MoveSelectionCommand(PassRefPtr<DocumentFragment>, const Position&, bool smartInsert, bool smartDelete);
+    MoveSelectionCommand(PassRefPtrWillBeRawPtr<DocumentFragment>, const Position&, bool smartInsert, bool smartDelete);
 
     virtual void doApply() OVERRIDE;
     virtual EditAction editingAction() const OVERRIDE;
 
-    RefPtr<DocumentFragment> m_fragment;
+    RefPtrWillBePersistent<DocumentFragment> m_fragment;
     Position m_position;
     bool m_smartInsert;
     bool m_smartDelete;