Prefetch @import files from CSS files.

Source/core/fetch/CSSStyleSheetResource.h

Index: Source/core/fetch/CSSStyleSheetResource.h
diff --git a/Source/core/fetch/CSSStyleSheetResource.h b/Source/core/fetch/CSSStyleSheetResource.h
index 83aabcd22871e5064279dcdfd8a4ec5411234099..cda03c443e588d56c2afcdf15a86518153c83666 100644
--- a/Source/core/fetch/CSSStyleSheetResource.h
+++ b/Source/core/fetch/CSSStyleSheetResource.h
@@ -28,6 +28,10 @@
 
 #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 {
 
@@ -38,7 +42,7 @@ 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;
@@ -54,11 +58,20 @@ public:
 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);