HTMLDocumentParser: Dedupe member inits by moving them into in-class init

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 165 matching lines @@
 
     void pumpPreloadQueue();
 
     PassOwnPtr<HTMLPreloadScanner> createPreloadScanner();
 
     int preloadInsertion(const SegmentedString& source);
     void evaluateAndPreloadScriptForDocumentWrite(const String& source);
 
     HTMLToken& token() { return *m_token; }
 
-    HTMLParserOptions m_options;
+    HTMLParserOptions m_options {document()};
     HTMLInputStream m_input;
 
     OwnPtr<HTMLToken> m_token;
     OwnPtr<HTMLTokenizer> m_tokenizer;
     Member<HTMLScriptRunner> m_scriptRunner;
     Member<HTMLTreeBuilder> m_treeBuilder;
     OwnPtr<HTMLPreloadScanner> m_preloadScanner;
     OwnPtr<HTMLPreloadScanner> m_insertionPreloadScanner;
-    OwnPtr<WebTaskRunner> m_loadingTaskRunner;
+    OwnPtr<WebTaskRunner> m_loadingTaskRunner = adoptPtr(document()->loadingTaskRunner()->clone());

[sof, 2016/06/08 06:02:04]

Is having non-const, dependent on field init order, initializers such a good
idea?

[kouhei (in TOK), 2016/06/08 06:07:17]

The background is that we found m_isParsingAtLineNumber uninitialized in  one of
the ctors.
I'm ok as long as we are able to avoid that kind of mistakes in the future.

I think the options are:
- This CL.
- Const trivially initialized members use in-class init. non-const members init
are duped.
- Make a private delegating constructor and initialize all members there. No
in-class init.

[sof, 2016/06/08 06:40:24]

Thanks for the context (and menu :) ), initializations needs to be commoned-up.
Would a delegating constructor be feasible & readable, i.e., not have too many
arguments?

[Yoav Weiss, 2016/06/08 08:43:27]

Just to make sure that I understand the problems sof sees in this CL, is it
related to the fact that document() is initialized first, and then used to
initialize the other members?

     Member<HTMLParserScheduler> m_parserScheduler;
     HTMLSourceTracker m_sourceTracker;
     TextPosition m_textPosition;
     XSSAuditor m_xssAuditor;
-    XSSAuditorDelegate m_xssAuditorDelegate;
+    XSSAuditorDelegate m_xssAuditorDelegate {document()};
 
     // FIXME: m_lastChunkBeforeScript, m_tokenizer, m_token, and m_input should be combined into a single state object
     // so they can be set and cleared together and passed between threads together.
     OwnPtr<ParsedChunk> m_lastChunkBeforeScript;
     Deque<OwnPtr<ParsedChunk>> m_speculations;
-    WeakPtrFactory<HTMLDocumentParser> m_weakFactory;
     WeakPtr<BackgroundHTMLParser> m_backgroundParser;
     Member<HTMLResourcePreloader> m_preloader;
     PreloadRequestStream m_queuedPreloads;
     Vector<String> m_queuedDocumentWriteScripts;
     RefPtr<ParsedChunkQueue> m_parsedChunkQueue;
-    OwnPtr<DocumentWriteEvaluator> m_evaluator;
+    OwnPtr<DocumentWriteEvaluator> m_evaluator = DocumentWriteEvaluator::create(*document());
 
     bool m_shouldUseThreading;
-    bool m_endWasDelayed;
-    bool m_haveBackgroundParser;
-    bool m_tasksWereSuspended;
-    unsigned m_pumpSessionNestingLevel;
-    unsigned m_pumpSpeculationsSessionNestingLevel;
-    bool m_isParsingAtLineNumber;
-    bool m_triedLoadingLinkHeaders;
+    bool m_endWasDelayed = false;
+    bool m_haveBackgroundParser = false;
+    bool m_tasksWereSuspended = false;
+    unsigned m_pumpSessionNestingLevel = 0;
+    unsigned m_pumpSpeculationsSessionNestingLevel = 0;
+    bool m_isParsingAtLineNumber = false;
+    bool m_triedLoadingLinkHeaders = false;
+
+    WeakPtrFactory<HTMLDocumentParser> m_weakFactory {this};
 };
 
 } // namespace blink
 
 #endif