Simplify some parsing-related code

sky/engine/core/dom/DocumentParser.cpp

 /*
  * Copyright (C) 2010 Google, Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 23 matching lines @@
 
 DocumentParser::DocumentParser(Document* document)
     : m_state(ParsingState)
     , m_document(document)
 {
     ASSERT(document);
 }
 
 DocumentParser::~DocumentParser()
 {
-#if !ENABLE(OILPAN)
     // Document is expected to call detach() before releasing its ref.
     // This ASSERT is slightly awkward for parsers with a fragment case
     // as there is no Document to release the ref.
     ASSERT(!m_document);
-#endif
-}
-
-void DocumentParser::trace(Visitor* visitor)
-{
-    visitor->trace(m_document);
 }
 
 void DocumentParser::prepareToStopParsing()
 {
     ASSERT(m_state == ParsingState);
     m_state = StoppingState;
 }
 
 void DocumentParser::stopParsing()
 {
     m_state = StoppedState;
 }
 
 void DocumentParser::detach()
 {
     m_state = DetachedState;
     m_document = nullptr;
 }
 
 };