Preload scan external css for @import

third_party/WebKit/Source/core/fetch/CSSStyleSheetResource.h

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller <mueller@kde.org>
     Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
     Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
     version 2 of the License, or (at your option) any later version.
@@ skipping 37 matching lines @@
     ~CSSStyleSheetResource() override;
     DECLARE_VIRTUAL_TRACE();
 
     const String sheetText(MIMETypeCheck = MIMETypeCheck::Strict) const;
 
     void didAddClient(ResourceClient*) override;
 
     StyleSheetContents* restoreParsedStyleSheet(const CSSParserContext&);
     void saveParsedStyleSheet(StyleSheetContents*);
 
+    void appendData(const char* data, size_t length) override;
+
 protected:
     bool isSafeToUnlock() const override;
     void destroyDecodedDataIfPossible() override;
     void destroyDecodedDataForFailedRevalidation() override { destroyDecodedDataIfPossible(); }
 
 private:
     class CSSStyleSheetResourceFactory : public ResourceFactory {
     public:
         CSSStyleSheetResourceFactory()
             : ResourceFactory(Resource::CSSStyleSheet) { }
 
         Resource* create(const ResourceRequest& request, const ResourceLoaderOptions& options, const String& charset) const override
         {
             return new CSSStyleSheetResource(request, options, charset);
         }
     };
     CSSStyleSheetResource(const ResourceRequest&, const ResourceLoaderOptions&, const String& charset);
 
     bool canUseSheet(MIMETypeCheck) const;
     void removedFromMemoryCache() override;
     void checkNotify() override;
 
     String m_decodedSheetText;
 
     Member<StyleSheetContents> m_parsedStyleSheetCache;
+
+    bool m_didNotifyFirstData;
 };
 
 DEFINE_RESOURCE_TYPE_CASTS(CSSStyleSheet);
 
 } // namespace blink
 
 #endif