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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 #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 {
+    WTF_MAKE_NONCOPYABLE(CSSPreloadScanner);
     DISALLOW_NEW();

[Yoav Weiss, 2016/03/30 21:38:31]

spurious change or is the order here meaningful?

[Charlie Harrison, 2016/03/31 03:59:59]

Oops, spurious. Sorry.

-    WTF_MAKE_NONCOPYABLE(CSSPreloadScanner);
 public:
     CSSPreloadScanner();
     ~CSSPreloadScanner();
 
     void reset();
 
     void scan(const HTMLToken::DataVector&, const SegmentedString&, PreloadRequestStream&, const KURL&);
     void scan(const String&, const SegmentedString&, PreloadRequestStream&, const KURL&);
 
     void setReferrerPolicy(const ReferrerPolicy);
@@ skipping 22 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 {
+public:
+    CSSPreloaderResourceClient(HTMLResourcePreloader*);
+    void didAppendData(const CSSStyleSheetResource*) override;
+    String debugName() const override { return "CSSPreloaderResourceClient"; }
+
+private:
+    void preloadChunk(const String& chunk, const CSSStyleSheetResource*);
+    CSSPreloadScanner m_cssPreloadScanner;
+    RawPtrWillBeWeakPersistent<HTMLResourcePreloader> m_preloader;
+    size_t m_streamPosition;
+};
+
 } // namespace blink
 
 #endif