Preload scan external CSS for @import

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

Index: third_party/WebKit/Source/core/html/parser/CSSPreloadScanner.h
diff --git a/third_party/WebKit/Source/core/html/parser/CSSPreloadScanner.h b/third_party/WebKit/Source/core/html/parser/CSSPreloadScanner.h
index b56ef885e8301e0609db0e85ab6ab34b236d835f..e42e5e14b4af1c1898acab09216fdaaa16002c7c 100644
--- a/third_party/WebKit/Source/core/html/parser/CSSPreloadScanner.h
+++ b/third_party/WebKit/Source/core/html/parser/CSSPreloadScanner.h
@@ -27,13 +27,15 @@
 #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();
@@ -80,6 +82,24 @@ private:
     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