Preload scan external CSS for @import

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

 /*
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  * Copyright (C) 2010 Google Inc. All Rights Reserved.
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  * modification, are permitted provided that the following conditions
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 #ifndef CSSPreloadScanner_h
 #define CSSPreloadScanner_h
 
-#include "core/html/parser/HTMLResourcePreloader.h"
+#include "core/fetch/StyleSheetResourceClient.h"
 #include "core/html/parser/HTMLToken.h"
+#include "core/html/parser/PreloadRequest.h"
 #include "wtf/text/StringBuilder.h"
 
 namespace blink {
 
 class SegmentedString;
+class HTMLResourcePreloader;
 
 class CSSPreloadScanner {
     DISALLOW_NEW();
     WTF_MAKE_NONCOPYABLE(CSSPreloadScanner);
 public:
     CSSPreloadScanner();
     ~CSSPreloadScanner();
 
     void reset();
 
@@ skipping 26 matching lines @@
     StringBuilder m_rule;
     StringBuilder m_ruleValue;
 
     ReferrerPolicy m_referrerPolicy = ReferrerPolicyDefault;
 
     // Below members only non-null during scan()
     PreloadRequestStream* m_requests = nullptr;
     const KURL* m_predictedBaseElementURL = nullptr;
 };
 
+// Each CSSPreloaderResourceClient keeps track of a single CSS resource, and
+// drives a CSSPreloadScanner as raw data arrives for it. This lets us preload
+// @import tags before parsing.
+class CSSPreloaderResourceClient : public StyleSheetResourceClient {

[hiroshige, 2016/06/17 12:15:17]

It's better to make CSSPreloaderResourceClient to inherit GarbageCollected and
ResourceOwner<StyleSheetResource>.
StyleSheetResourceClient is now GarbageCollectedMixin.

[Charlie Harrison, 2016/07/13 18:18:14]

Done.

+public:
+    CSSPreloaderResourceClient(Resource*, HTMLResourcePreloader*);
+    ~CSSPreloaderResourceClient();
+    void notifyFinished(Resource*) override;

[hiroshige, 2016/06/17 12:15:17]

notifyFinished() is not called for StyleSheetResourceClient.
setCSSStyleSheet() or setXSLStyleSheet() is called instead when finished.

[Charlie Harrison, 2016/07/13 18:18:14]

Replaced it with setCSSStyleSheet().

+    void didAppendFirstData(const CSSStyleSheetResource*) override;
+    String debugName() const override { return "CSSPreloaderResourceClient"; }
+
+private:
+    void clearResource();
+    void scanCSS(const CSSStyleSheetResource*);
+    Persistent<Resource> m_resource;
+    WeakPersistent<HTMLResourcePreloader> m_preloader;
+};
+
 } // namespace blink
 
 #endif