Oilpan: Reapply: Remove all the RefPtrs and most of the raw pointers to style

Source/core/xml/XSLStyleSheetLibxslt.cpp

 /*
  * This file is part of the XSL implementation.
  *
  * Copyright (C) 2004, 2005, 2006, 2008, 2012 Apple Inc. All rights reserved.
  *
  * 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.
  *
@@ skipping 44 matching lines @@
 XSLStyleSheet::XSLStyleSheet(Node* parentNode, const String& originalURL, const KURL& finalURL,  bool embedded)
     : m_ownerNode(parentNode)
     , m_originalURL(originalURL)
     , m_finalURL(finalURL)
     , m_isDisabled(false)
     , m_embedded(embedded)
     , m_processed(true) // The root sheet starts off processed.
     , m_stylesheetDoc(0)
     , m_stylesheetDocTaken(false)
     , m_compilationFailed(false)
-    , m_parentStyleSheet(0)
+    , m_parentStyleSheet(nullptr)
 {
 }
 
 XSLStyleSheet::~XSLStyleSheet()
 {
     if (!m_stylesheetDocTaken)
         xmlFreeDoc(m_stylesheetDoc);
 
     for (unsigned i = 0; i < m_children.size(); ++i) {
         ASSERT(m_children.at(i)->parentStyleSheet() == this);
@@ skipping 220 matching lines @@
 }
 
 void XSLStyleSheet::markAsProcessed()
 {
     ASSERT(!m_processed);
     ASSERT(!m_stylesheetDocTaken);
     m_processed = true;
     m_stylesheetDocTaken = true;
 }
 
-void XSLStyleSheet::trace(Visitor*)
+void XSLStyleSheet::trace(Visitor* visitor)
 {
+    visitor->trace(m_parentStyleSheet);
 }
 
 } // namespace WebCore