Oilpan: have xml/ objects on the heap by default.

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 210 matching lines @@
                 loadChildSheet(String::fromUTF8((const char*)uriRef));
                 xmlFree(uriRef);
             }
             curr = curr->next;
         }
     }
 }
 
 void XSLStyleSheet::loadChildSheet(const String& href)
 {
-    OwnPtrWillBeRawPtr<XSLImportRule> childRule = XSLImportRule::create(this, href);
-    XSLImportRule* c = childRule.get();
-    m_children.append(childRule.release());
-    c->loadSheet();
+    XSLImportRule* childRule = XSLImportRule::create(this, href);
+    m_children.append(childRule);
+    childRule->loadSheet();
 }
 
 xsltStylesheetPtr XSLStyleSheet::compileStyleSheet()
 {
     // FIXME: Hook up error reporting for the stylesheet compilation process.
     if (m_embedded)
         return xsltLoadStylesheetPI(document());
 
     // Certain libxslt versions are corrupting the xmlDoc on compilation
     // failures - hence attempting to recompile after a failure is unsafe.
@@ skipping 75 matching lines @@
 DEFINE_TRACE(XSLStyleSheet)
 {
     visitor->trace(m_ownerNode);
     visitor->trace(m_children);
     visitor->trace(m_parentStyleSheet);
     visitor->trace(m_ownerDocument);
     StyleSheet::trace(visitor);
 }
 
 } // namespace blink