Add <link rel=preconnect> support to the HTMLPreloadScanner

Source/core/loader/Preconnecter.cpp

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+#include "core/loader/Preconnecter.h"
+
+#include "platform/network/NetworkHints.h"
+#include "wtf/PassOwnPtr.h"
+
+namespace blink {
+
+PassOwnPtr<PreconnecterHost> Preconnecter::create()
+{
+    return adoptPtr(new Preconnecter());
+}
+
+void Preconnecter::preconnect(KURL& host, CrossOriginAttributeValue crossOrigin)
+{
+    preconnect(host, crossOrigin);
+}
+
+}; // namespace blink