Revert of Added <link rel=preconnect> crossorigin attribute

Source/core/html/CrossOriginAttribute.cpp

Index: Source/core/html/CrossOriginAttribute.cpp
diff --git a/Source/core/html/CrossOriginAttribute.cpp b/Source/core/html/CrossOriginAttribute.cpp
deleted file mode 100644
index a8b2f695521bcd7e56cdefb5db8ed88b7b00d024..0000000000000000000000000000000000000000
--- a/Source/core/html/CrossOriginAttribute.cpp
+++ /dev/null
@@ -1,20 +0,0 @@
-// 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/html/CrossOriginAttribute.h"
-
-namespace blink {
-
-CrossOriginAttributeValue crossOriginAttributeValue(const String& value)
-{
-    if (value.isNull())
-        return CrossOriginAttributeNotSet;
-    if (equalIgnoringCase(value, "use-credentials"))
-        return CrossOriginAttributeUseCredentials;
-    return CrossOriginAttributeAnonymous;
-}
-
-} // namespace blink
-