Update HTTPHeaderMap wrappers to use AtomicString type for header values

Source/platform/network/HTTPParsers.h

 /*
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2011 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
@@ skipping 58 matching lines @@
     FilterReflectedXSS,
     BlockReflectedXSS
 };
 
 PLATFORM_EXPORT ContentDispositionType contentDispositionType(const String&);
 PLATFORM_EXPORT bool isValidHTTPHeaderValue(const String&);
 PLATFORM_EXPORT bool isValidHTTPToken(const String&);
 PLATFORM_EXPORT bool parseHTTPRefresh(const String& refresh, bool fromHttpEquivMeta, double& delay, String& url);
 PLATFORM_EXPORT double parseDate(const String&);
 PLATFORM_EXPORT String filenameFromHTTPContentDisposition(const String&);
-PLATFORM_EXPORT String extractMIMETypeFromMediaType(const String&);
+PLATFORM_EXPORT AtomicString extractMIMETypeFromMediaType(const AtomicString&);
 PLATFORM_EXPORT String extractCharsetFromMediaType(const String&);
 PLATFORM_EXPORT void findCharsetInMediaType(const String& mediaType, unsigned& charsetPos, unsigned& charsetLen, unsigned start = 0);
 PLATFORM_EXPORT ReflectedXSSDisposition parseXSSProtectionHeader(const String& header, String& failureReason, unsigned& failurePosition, String& reportURL);
 PLATFORM_EXPORT String extractReasonPhraseFromHTTPStatusLine(const String&);
 PLATFORM_EXPORT XFrameOptionsDisposition parseXFrameOptionsHeader(const String&);
 
 // -1 could be set to one of the return parameters to indicate the value is not specified.
 PLATFORM_EXPORT bool parseRange(const String&, long long& rangeOffset, long long& rangeEnd, long long& rangeSuffixLength);
 
 PLATFORM_EXPORT ContentTypeOptionsDisposition parseContentTypeOptionsHeader(const String& header);
 
 // Parsing Complete HTTP Messages.
 enum HTTPVersion { Unknown, HTTP_1_0, HTTP_1_1 };
 PLATFORM_EXPORT size_t parseHTTPRequestLine(const char* data, size_t length, String& failureReason, String& method, String& url, HTTPVersion&);
-PLATFORM_EXPORT size_t parseHTTPHeader(const char* data, size_t length, String& failureReason, AtomicString& nameStr, String& valueStr);
+PLATFORM_EXPORT size_t parseHTTPHeader(const char* data, size_t length, String& failureReason, AtomicString& nameStr, AtomicString& valueStr);
 PLATFORM_EXPORT size_t parseHTTPRequestBody(const char* data, size_t length, Vector<unsigned char>& body);
 
 }
 
 #endif