Preload scan external CSS for @import

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

Index: third_party/WebKit/Source/core/html/parser/HTMLResourcePreloader.h
diff --git a/third_party/WebKit/Source/core/html/parser/HTMLResourcePreloader.h b/third_party/WebKit/Source/core/html/parser/HTMLResourcePreloader.h
index 29ddf17c574e2bce23e8509bcf9d9598b3d8f087..dd81bc2f81b1b4d58592917fdbf68a88eca63ef5 100644
--- a/third_party/WebKit/Source/core/html/parser/HTMLResourcePreloader.h
+++ b/third_party/WebKit/Source/core/html/parser/HTMLResourcePreloader.h
@@ -28,6 +28,7 @@
 
 #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"
@@ -36,11 +37,13 @@
 
 namespace blink {
 
-class CORE_EXPORT HTMLResourcePreloader final : public GarbageCollected<HTMLResourcePreloader>, public ResourcePreloader {
+class CORE_EXPORT HTMLResourcePreloader final : public GarbageCollectedFinalized<HTMLResourcePreloader>, public ResourcePreloader {
     WTF_MAKE_NONCOPYABLE(HTMLResourcePreloader);
     friend class HTMLResourcePreloaderTest;
 public:
     static HTMLResourcePreloader* create(Document&);
+    int countPreloads();
+    Document* document() { return m_document.get(); }
     DECLARE_TRACE();
 
 protected:
@@ -50,6 +53,7 @@ private:
     explicit HTMLResourcePreloader(Document&);
 
     Member<Document> m_document;
+    HashSet<OwnPtr<CSSPreloaderResourceClient>> m_cssPreloaders;
 };
 
 } // namespace blink