Normalize and update the header value checks to RFC 7230 for 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 "core/CoreExport.h"
 #include "wtf/Allocator.h"
 #include "wtf/Forward.h"
 
 namespace blink {
 
 class HTTPHeaderMap;
 
 class CORE_EXPORT FetchUtils {
     STATIC_ONLY(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&);
     static AtomicString normalizeMethod(const AtomicString& method);
+    static String normalizeHeaderValue(const String& value);
 };
 
 } // namespace blink
 
 #endif