Enable Oilpan for core/xml/

Source/core/xml/XPathNodeSet.cpp

Index: Source/core/xml/XPathNodeSet.cpp
diff --git a/Source/core/xml/XPathNodeSet.cpp b/Source/core/xml/XPathNodeSet.cpp
index 0d14afd89ce05d5c0f783202004d0d6541f3b565..b57bc5c2f2992bfcd3807e1efcb62bf2fada52dd 100644
--- a/Source/core/xml/XPathNodeSet.cpp
+++ b/Source/core/xml/XPathNodeSet.cpp
@@ -41,13 +41,20 @@ const unsigned traversalSortCutoff = 10000;
 
 typedef WillBeHeapVector<RawPtrWillBeMember<Node> > NodeSetVector;
 
-PassOwnPtrWillBeRawPtr<NodeSet> NodeSet::create(const NodeSet& other)
+NodeSet* NodeSet::create(const NodeSet& other)
 {
-    OwnPtrWillBeRawPtr<NodeSet> nodeSet = NodeSet::create();
+    NodeSet* nodeSet = NodeSet::create();
     nodeSet->m_isSorted = other.m_isSorted;
     nodeSet->m_subtreesAreDisjoint = other.m_subtreesAreDisjoint;
     nodeSet->m_nodes.appendVector(other.m_nodes);
-    return nodeSet.release();
+    return nodeSet;
+}
+
+void NodeSet::trace(Visitor* visitor)
+{
+#if ENABLE(OILPAN)
+    visitor->trace(m_nodes);
+#endif
 }
 
 static inline Node* parentWithDepth(unsigned depth, const NodeSetVector& parents)