delete useThreading flag as it is always true

Source/core/html/parser/HTMLDocumentParser.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 88 matching lines @@
         return 0;
     }
 
 private:
     WeakPtr<BackgroundHTMLParser> m_backgroundParser;
 };
 
 HTMLDocumentParser::HTMLDocumentParser(HTMLDocument& document, bool reportErrors)
     : ScriptableDocumentParser(document)
     , m_options(&document)
-    , m_token(m_options.useThreading ? nullptr : adoptPtr(new HTMLToken))
-    , m_tokenizer(m_options.useThreading ? nullptr : HTMLTokenizer::create(m_options))
+    , m_token(nullptr)
+    , m_tokenizer(nullptr)
     , m_scriptRunner(HTMLScriptRunner::create(&document, this))
     , m_treeBuilder(HTMLTreeBuilder::create(this, &document, parserContentPolicy(), reportErrors, m_options))
     , m_parserScheduler(HTMLParserScheduler::create(this))
     , m_xssAuditorDelegate(&document)
     , m_weakFactory(this)
     , m_preloader(HTMLResourcePreloader::create(document))
     , m_isPinnedToMainThread(false)
     , m_endWasDelayed(false)
     , m_haveBackgroundParser(false)
     , m_pumpSessionNestingLevel(0)
@@ skipping 946 matching lines @@
 void HTMLDocumentParser::setDecoder(PassOwnPtr<TextResourceDecoder> decoder)
 {
     ASSERT(decoder);
     DecodedDataDocumentParser::setDecoder(decoder);
 
     if (m_haveBackgroundParser)
         HTMLParserThread::shared()->postTask(bind(&BackgroundHTMLParser::setDecoder, m_backgroundParser, takeDecoder()));
 }
 
 }