Preload scan external css for @import

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

 /*
  * Copyright (C) 2013 Google Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 10 matching lines @@
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef HTMLResourcePreloader_h
 #define HTMLResourcePreloader_h
 
 #include "core/fetch/FetchRequest.h"
 #include "core/fetch/Resource.h"
+#include "core/html/parser/CSSPreloadScanner.h"
 #include "core/html/parser/PreloadRequest.h"
 #include "core/html/parser/ResourcePreloader.h"
 #include "core/loader/NetworkHintsInterface.h"
 #include "wtf/CurrentTime.h"
 #include "wtf/text/TextPosition.h"
 
 namespace blink {
 
-class CORE_EXPORT HTMLResourcePreloader final : public NoBaseWillBeGarbageCollected<HTMLResourcePreloader>, public ResourcePreloader {
+class CORE_EXPORT HTMLResourcePreloader final : public NoBaseWillBeGarbageCollectedFinalized<HTMLResourcePreloader>, public ResourcePreloader {
     WTF_MAKE_NONCOPYABLE(HTMLResourcePreloader); USING_FAST_MALLOC_WILL_BE_REMOVED(HTMLResourcePreloader);
     friend class HTMLResourcePreloaderTest;
 public:
     static PassOwnPtrWillBeRawPtr<HTMLResourcePreloader> create(Document&);
     DECLARE_TRACE();
 
 protected:
     void preload(PassOwnPtr<PreloadRequest>, const NetworkHintsInterface&) override;
 
 private:
     explicit HTMLResourcePreloader(Document&);
 
     RawPtrWillBeMember<Document> m_document;
+    HashSet<OwnPtr<CSSPreloaderResourceClient>> m_cssPreloaders;
 };
 
 } // namespace blink
 
 #endif