Prefetch @import files from CSS files.

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 10 matching lines @@
 
     This class provides all functionality needed for loading images, style sheets and html
     pages from the web. It has a memory cache for these objects.
 */
 
 #ifndef CSSStyleSheetResource_h
 #define CSSStyleSheetResource_h
 
 #include "core/fetch/ResourcePtr.h"
 #include "core/fetch/StyleSheetResource.h"
+#include "core/html/parser/BackgroundHTMLInputStream.h"
+#include "core/html/parser/CSSPreloadScanner.h"
+#include "core/html/parser/HTMLParserOptions.h"
+#include "core/html/parser/HTMLTokenizer.h"

[abarth-chromium, 2014/02/15 18:48:48]

Woah there.  Fetch shouldn't need to know about any of these detailed things
from the parser.

 
 namespace WebCore {
 
 class CSSParserContext;
 class ResourceClient;
 class StyleSheetContents;
 class TextResourceDecoder;
 
 class CSSStyleSheetResource FINAL : public StyleSheetResource {
 public:
-    CSSStyleSheetResource(const ResourceRequest&, const String& charset);
+    CSSStyleSheetResource(const ResourceRequest&, const String& charset, Document*);

[abarth-chromium, 2014/02/15 18:48:48]

Resources shouldn't be specific to documents.

     virtual ~CSSStyleSheetResource();
 
     const String sheetText(bool enforceMIMEType = true, bool* hasValidMIMEType = 0) const;
 
     virtual void didAddClient(ResourceClient*) OVERRIDE;
     virtual void setEncoding(const String&) OVERRIDE;
     virtual String encoding() const OVERRIDE;
     virtual void destroyDecodedData() OVERRIDE;
 
     PassRefPtr<StyleSheetContents> restoreParsedStyleSheet(const CSSParserContext&);
     void saveParsedStyleSheet(PassRefPtr<StyleSheetContents>);
 
 private:
     bool canUseSheet(bool enforceMIMEType, bool* hasValidMIMEType) const;
     virtual void checkNotify() OVERRIDE;
+    virtual void appendData(const char*, int);
+    void prescan(const char* data);
 
     OwnPtr<TextResourceDecoder> m_decoder;
     String m_decodedSheetText;
 
     RefPtr<StyleSheetContents> m_parsedStyleSheetCache;
+    HTMLParserOptions m_options;
+    OwnPtr<HTMLTokenizer> m_tokenizer;

[eseidel, 2014/02/14 12:15:41]

This seems wrong.  Do other resources own a Tokenizer?

[eseidel, 2014/02/14 12:16:57]

Why would each resource want its own tokenizer/scanner, etc?  Seems like this
could be done via a shared, even static method.  The whole CSS file is going to
be processed in one go.

+    OwnPtr<CSSPreloadScanner> m_preloadScanner;
+    OwnPtr<BackgroundHTMLInputStream> m_input;
+    OwnPtr<HTMLToken> m_token;
+    OwnPtr<HTMLResourcePreloader> m_preloader;
+    bool m_prescan;
 };
 
 DEFINE_RESOURCE_TYPE_CASTS(CSSStyleSheet);
 
 }
 
 #endif