Oilpan: make DocumentFragment a heap allocated object.

Source/core/editing/ReplaceSelectionCommand.h

Index: Source/core/editing/ReplaceSelectionCommand.h
diff --git a/Source/core/editing/ReplaceSelectionCommand.h b/Source/core/editing/ReplaceSelectionCommand.h
index df93c47eac9ac44181a0f8d07824f6e04bf11c7f..dd2a31f096e77960215438ea22fb80ba834fe019 100644
--- a/Source/core/editing/ReplaceSelectionCommand.h
+++ b/Source/core/editing/ReplaceSelectionCommand.h
@@ -47,13 +47,13 @@ public:
 
     typedef unsigned CommandOptions;
 
-    static PassRefPtr<ReplaceSelectionCommand> create(Document& document, PassRefPtr<DocumentFragment> fragment, CommandOptions options, EditAction action = EditActionPaste)
+    static PassRefPtr<ReplaceSelectionCommand> create(Document& document, PassRefPtrWillBeRawPtr<DocumentFragment> fragment, CommandOptions options, EditAction action = EditActionPaste)
     {
         return adoptRef(new ReplaceSelectionCommand(document, fragment, options, action));
     }
 
 private:
-    ReplaceSelectionCommand(Document&, PassRefPtr<DocumentFragment>, CommandOptions, EditAction);
+    ReplaceSelectionCommand(Document&, PassRefPtrWillBeRawPtr<DocumentFragment>, CommandOptions, EditAction);
 
     virtual void doApply() OVERRIDE;
     virtual EditAction editingAction() const OVERRIDE;
@@ -108,7 +108,7 @@ private:
     bool m_selectReplacement;
     bool m_smartReplace;
     bool m_matchStyle;
-    RefPtr<DocumentFragment> m_documentFragment;
+    RefPtrWillBePersistent<DocumentFragment> m_documentFragment;
     bool m_preventNesting;
     bool m_movingParagraph;
     EditAction m_editAction;