Update HTTPHeaderMap wrappers to use AtomicString type for header values

Source/platform/network/HTTPParsers.cpp

 /*
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. http://www.torchmobile.com/
  * 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:
@@ skipping 248 matching lines @@
         // Remove quotes if there are any
         if (value[0] == '\"')
             value = value.substring(1, value.length() - 2);
 
         return value;
     }
 
     return String();
 }
 
-String extractMIMETypeFromMediaType(const String& mediaType)
+AtomicString extractMIMETypeFromMediaType(const AtomicString& mediaType)
 {
     StringBuilder mimeType;
     unsigned length = mediaType.length();
     mimeType.reserveCapacity(length);
     for (unsigned i = 0; i < length; i++) {
         UChar c = mediaType[i];
 
         if (c == ';')
             break;
 
@@ skipping 11 matching lines @@
         // includes only a few specific ASCII characters; a small subset of isSpaceOrNewline.
         // See https://bugs.webkit.org/show_bug.cgi?id=8644 for a bug tracking part of this.
         if (isSpaceOrNewline(c))
             continue;
 
         mimeType.append(c);
     }
 
     if (mimeType.length() == length)
         return mediaType;
-    return mimeType.toString();
+    return mimeType.toAtomicString();
 }
 
 String extractCharsetFromMediaType(const String& mediaType)
 {
     unsigned pos, len;
     findCharsetInMediaType(mediaType, pos, len);
     return mediaType.substring(pos, len);
 }
 
 void findCharsetInMediaType(const String& mediaType, unsigned& charsetPos, unsigned& charsetLen, unsigned start)
@@ skipping 288 matching lines @@
     else if (httpVersionString[7] == '0')
         httpVersion = HTTP_1_0;
     else if (httpVersionString[7] == '1')
         httpVersion = HTTP_1_1;
     else
         httpVersion = Unknown;
 
     return end - data;
 }
 
-size_t parseHTTPHeader(const char* start, size_t length, String& failureReason, AtomicString& nameStr, String& valueStr)
+size_t parseHTTPHeader(const char* start, size_t length, String& failureReason, AtomicString& nameStr, AtomicString& valueStr)
 {
     const char* p = start;
     const char* end = start + length;
 
     Vector<char> name;
     Vector<char> value;
-    nameStr = AtomicString();
-    valueStr = String();
+    nameStr = nullAtom;
+    valueStr = nullAtom;
 
     for (; p < end; p++) {
         switch (*p) {
         case '\r':
             if (name.isEmpty()) {
                 if (p + 1 < end && *(p + 1) == '\n')
                     return (p + 2) - start;
                 failureReason = "CR doesn't follow LF at " + trimInputSample(p, end - p);
                 return 0;
             }
@@ skipping 29 matching lines @@
         if (*p == '\r') {
             ++p;
             break;
         }
     }
     if (p >= end || *p != '\n') {
         failureReason = "CR doesn't follow LF after value at " + trimInputSample(p, end - p);
         return 0;
     }
     nameStr = AtomicString::fromUTF8(name.data(), name.size());
-    valueStr = String::fromUTF8(value.data(), value.size());
+    valueStr = AtomicString::fromUTF8(value.data(), value.size());
     if (nameStr.isNull()) {
         failureReason = "Invalid UTF-8 sequence in header name";
         return 0;
     }
     if (valueStr.isNull()) {
         failureReason = "Invalid UTF-8 sequence in header value";
         return 0;
     }
     return p - start;
 }
 
 size_t parseHTTPRequestBody(const char* data, size_t length, Vector<unsigned char>& body)
 {
     body.clear();
     body.append(data, length);
 
     return length;
 }
 
 }