Add HTMLResourcePreloader preconnect unit tests

Source/core/html/parser/HTMLResourcePreloader.h

Index: Source/core/html/parser/HTMLResourcePreloader.h
diff --git a/Source/core/html/parser/HTMLResourcePreloader.h b/Source/core/html/parser/HTMLResourcePreloader.h
index df0b3ef8e3eb29b3f5f53c5b8ce670c40ee91ab4..ada54bee3a23dead842f09a0c8fef1df3ee6c9bb 100644
--- a/Source/core/html/parser/HTMLResourcePreloader.h
+++ b/Source/core/html/parser/HTMLResourcePreloader.h
@@ -30,6 +30,7 @@
 #include "core/fetch/Resource.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"
 
@@ -37,12 +38,13 @@ namespace blink {
 
 class HTMLResourcePreloader final : public NoBaseWillBeGarbageCollected<HTMLResourcePreloader>, public ResourcePreloader {
     WTF_MAKE_NONCOPYABLE(HTMLResourcePreloader); WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED(HTMLResourcePreloader);
+    friend class HTMLResourcePreloaderTest;
 public:
-    static PassOwnPtrWillBeRawPtr<HTMLResourcePreloader> create(Document&);
+    static CORE_EXPORT PassOwnPtrWillBeRawPtr<HTMLResourcePreloader> create(Document&);
     DECLARE_TRACE();
 
 protected:
-    void preload(PassOwnPtr<PreloadRequest>) override;
+    CORE_EXPORT void preload(PassOwnPtr<PreloadRequest>, const NetworkHintsInterface&) override;
 
 private:
     explicit HTMLResourcePreloader(Document&);