[@import scanner] Don't access Document::settings() from appendData callback

third_party/WebKit/Source/core/html/parser/CSSPreloadScanner.cpp

 /*
  * Copyright (C) 2008, 2010 Apple Inc. All Rights Reserved.
  * Copyright (C) 2009 Torch Mobile, Inc. http://www.torchmobile.com/
  * 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.
@@ skipping 223 matching lines @@
         m_state = Initial;
     } else if (equalIgnoringCase(m_rule, "charset"))
         m_state = Initial;
     else
         m_state = DoneParsingImportRules;
     m_rule.clear();
     m_ruleValue.clear();
 }
 
 CSSPreloaderResourceClient::CSSPreloaderResourceClient(Resource* resource, HTMLResourcePreloader* preloader)
-    : m_preloader(preloader)
+    : m_policy(preloader->document()->settings()->cssExternalScannerPreload() ? ScanAndPreload : ScanOnly)
+    , m_preloader(preloader)
 {
     DCHECK(resource->getType() == Resource::Type::CSSStyleSheet);
     setResource(toCSSStyleSheetResource(resource), Resource::DontMarkAsReferenced);
 }
 
 CSSPreloaderResourceClient::~CSSPreloaderResourceClient()
 {
 }
 
 void CSSPreloaderResourceClient::setCSSStyleSheet(const String& href, const KURL& baseURL, const String& charset, const CSSStyleSheetResource*)
@@ skipping 29 matching lines @@
     cssScanTimeHistogram.count((monotonicallyIncreasingTimeMS() - startTime) * 1000);
     fetchPreloads(preloads);
 }
 
 void CSSPreloaderResourceClient::fetchPreloads(PreloadRequestStream& preloads)
 {
     if (preloads.size()) {
         m_preloader->document()->loader()->didObserveLoadingBehavior(WebLoadingBehaviorFlag::WebLoadingBehaviorCSSPreloadFound);
     }
 
-    Settings* settings = m_preloader->document()->settings();
-    DCHECK(settings);
-    if (settings->cssExternalScannerPreload()) {
+    if (m_policy == ScanAndPreload) {
         int currentPreloadCount = m_preloader->countPreloads();
         m_preloader->takeAndPreload(preloads);
         DEFINE_STATIC_LOCAL(CustomCountHistogram, cssImportHistogram, ("PreloadScanner.ExternalCSS.PreloadCount", 1, 100, 50));
         cssImportHistogram.count(m_preloader->countPreloads() - currentPreloadCount);
     }
 }
 
 DEFINE_TRACE(CSSPreloaderResourceClient)
 {
     visitor->trace(m_preloader);
     ResourceOwner<CSSStyleSheetResource>::trace(visitor);
 }
 
 } // namespace blink