Add <link rel=preconnect> support to the HTMLPreloadScanner

Source/core/loader/Preconnecter.h

Index: Source/core/loader/Preconnecter.h
diff --git a/Source/core/loader/Preconnecter.h b/Source/core/loader/Preconnecter.h
new file mode 100644
index 0000000000000000000000000000000000000000..0826473bdbf0526af10200be4c5c8bddb1b58de6
--- /dev/null
+++ b/Source/core/loader/Preconnecter.h
@@ -0,0 +1,29 @@
+// 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.
+
+#ifndef Preconnecter_h
+#define Preconnecter_h
+
+#include "core/html/CrossOriginAttribute.h"
+#include "platform/weborigin/KURL.h"
+
+namespace blink {
+
+class PreconnecterHost {
+public:
+    virtual void preconnect(KURL& host, CrossOriginAttributeValue) = 0;
+    virtual ~PreconnecterHost() { }
+};
+
+class Preconnecter : public PreconnecterHost {
+public:
+    static PassOwnPtr<PreconnecterHost> create();
+    virtual ~Preconnecter() { }
+
+    virtual void preconnect(KURL& host, CrossOriginAttributeValue);
+};
+
+}; // namespace blink
+
+#endif