Enable Oilpan for core/xml/

Source/core/xml/XMLSerializer.h

Index: Source/core/xml/XMLSerializer.h
diff --git a/Source/core/xml/XMLSerializer.h b/Source/core/xml/XMLSerializer.h
index 38b3131d034b78981c7a1c439eddb51fe9b9d448..edd8b81f70f97061431c45838d02b531ff79c5a4 100644
--- a/Source/core/xml/XMLSerializer.h
+++ b/Source/core/xml/XMLSerializer.h
@@ -22,21 +22,18 @@
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "platform/heap/Handle.h"
-#include "wtf/Forward.h"
-#include "wtf/PassRefPtr.h"
-#include "wtf/RefCounted.h"
 
 namespace blink {
 
 class ExceptionState;
 class Node;
 
-class XMLSerializer final : public RefCountedWillBeGarbageCollected<XMLSerializer>, public ScriptWrappable {
+class XMLSerializer final : public GarbageCollected<XMLSerializer>, public ScriptWrappable {
     DEFINE_WRAPPERTYPEINFO();
 public:
-    static PassRefPtrWillBeRawPtr<XMLSerializer> create()
+    static XMLSerializer* create()
     {
-        return adoptRefWillBeNoop(new XMLSerializer);
+        return new XMLSerializer;
     }
 
     String serializeToString(Node*, ExceptionState&);