Fix HTMLDocumentParser::stopBackgroundParser crash

third_party/WebKit/Source/core/html/parser/HTMLDocumentParser.h

 /*
  * 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 51 matching lines @@
 class HTMLDocument;
 class HTMLParserScheduler;
 class HTMLResourcePreloader;
 class HTMLScriptRunner;
 class HTMLTreeBuilder;
 class PumpSession;
 class TokenizedChunkQueue;
 
 class HTMLDocumentParser :  public ScriptableDocumentParser, private HTMLScriptRunnerHost {
     USING_GARBAGE_COLLECTED_MIXIN(HTMLDocumentParser);
+    USING_PRE_FINALIZER(HTMLDocumentParser, dispose);
 public:
     static HTMLDocumentParser* create(HTMLDocument& document, ParserSynchronizationPolicy backgroundParsingPolicy)
     {
         return new HTMLDocumentParser(document, backgroundParsingPolicy);
     }
     ~HTMLDocumentParser() override;
     DECLARE_VIRTUAL_TRACE();
 
+    // TODO(alexclarke): Remove when background parser goes away.
+    void dispose();
+
     // Exposed for HTMLParserScheduler
     void resumeParsingAfterYield();
 
     static void parseDocumentFragment(const String&, DocumentFragment*, Element* contextElement, ParserContentPolicy = AllowScriptingContent);
 
     HTMLTokenizer* tokenizer() const { return m_tokenizer.get(); }
 
     TextPosition textPosition() const final;
     bool isParsingAtLineNumber() const final;
     OrdinalNumber lineNumber() const final;
@@ skipping 142 matching lines @@
     bool m_tasksWereSuspended;
     unsigned m_pumpSessionNestingLevel;
     unsigned m_pumpSpeculationsSessionNestingLevel;
     bool m_isParsingAtLineNumber;
     bool m_triedLoadingLinkHeaders;
 };
 
 } // namespace blink
 
 #endif