Move fetch-related predicates to core/fetch.

Source/core/fetch/FetchUtils.h

+// Copyright 2014 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 FetchUtils_h
+#define FetchUtils_h
+
+#include "wtf/Forward.h"
+
+namespace blink {
+
+class HTTPHeaderMap;
+
+class FetchUtils {
+public:
+    static bool isSimpleMethod(const String& method);
+    static bool isSimpleHeader(const AtomicString& name, const AtomicString& value);
+    static bool isSimpleRequest(const String& method, const HTTPHeaderMap&);
+    static bool isForbiddenMethod(const String& method);
+    static bool isUsefulMethod(const String& method) { return !isForbiddenMethod(method); }
+    static bool isForbiddenHeaderName(const String& name);
+    static bool isForbiddenResponseHeaderName(const String& name);
+    static bool isSimpleOrForbiddenRequest(const String& method, const HTTPHeaderMap&);
+
+private:
+    FetchUtils(); // = delete;
+};
+
+} // namespace blink
+
+#endif