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 b5c7b5231c7cb36a2fdcdbd6377612108b35b655..032c2d79d5432bc6fdda57accba2e304be54e08f 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"
@@ -36,7 +37,7 @@
 
 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:
@@ -50,6 +51,7 @@ private:
     explicit HTMLResourcePreloader(Document&);
 
     RawPtrWillBeMember<Document> m_document;
+    HashSet<OwnPtr<CSSPreloaderResourceClient>> m_cssPreloaders;
 };
 
 } // namespace blink