2. Remove HTMLParserScriptRunner's prefinalizer

third_party/WebKit/Source/core/html/parser/HTMLParserScriptRunner.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 37 matching lines @@
 //
 // If a script blocks parsing, this class is responsible for holding it, and
 // executing it when required.
 //
 // An HTMLParserScriptRunner is owned by its host, an HTMLDocumentParser.
 class HTMLParserScriptRunner final
     : public GarbageCollectedFinalized<HTMLParserScriptRunner>,
       private PendingScriptClient {
   WTF_MAKE_NONCOPYABLE(HTMLParserScriptRunner);
   USING_GARBAGE_COLLECTED_MIXIN(HTMLParserScriptRunner);
-  USING_PRE_FINALIZER(HTMLParserScriptRunner, Detach);
 
  public:
   static HTMLParserScriptRunner* Create(HTMLParserReentryPermit* reentry_permit,
                                         Document* document,
                                         HTMLParserScriptRunnerHost* host) {
     return new HTMLParserScriptRunner(reentry_permit, document, host);
   }
   ~HTMLParserScriptRunner();
 
-  // Prepares this object to be destroyed. Invoked when the parser is detached,
-  // or failing that, as a pre-finalizer.
+  // Invoked when the parser is detached.
+  //
+  // We don't need to call Detach() as a prefinalizer, because PendingScripts
+  // are Dispose()d in PendingScripts' prefinalizers.
   void Detach();
 
   // Processes the passed in script and any pending scripts if possible.
   // This does not necessarily run the script immediately. For instance,
   // execution may not happen until the script loads from the network, or after
   // the document finishes parsing.
   void ProcessScriptElement(Element*,
                             const TextPosition& script_start_position);
 
   // Invoked when the parsing-blocking script resource has loaded, to execute
@@ skipping 50 matching lines @@
   // https://html.spec.whatwg.org/#pending-parsing-blocking-script
   Member<PendingScript> parser_blocking_script_;
 
   // https://html.spec.whatwg.org/#list-of-scripts-that-will-execute-when-the-document-has-finished-parsing
   HeapDeque<Member<PendingScript>> scripts_to_execute_after_parsing_;
 };
 
 }  // namespace blink
 
 #endif