Update code that previously constructed strings from string iterators only to...

net/http/http_chunked_decoder.cc

 // Copyright (c) 2010 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.
 
 // Derived from:
 //   mozilla/netwerk/protocol/http/src/nsHttpChunkedDecoder.cpp
 // The license block is:
 /* ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  *
@@ skipping 174 matching lines @@
   while (len && start[len - 1] == ' ')
     len--;
 
   // Be more restrictive than HexStringToInt;
   // don't allow inputs with leading "-", "+", "0x", "0X"
   if (base::StringPiece(start, len).find_first_not_of("0123456789abcdefABCDEF")
       != base::StringPiece::npos)
     return false;
 
   int parsed_number;
-  bool ok = base::HexStringToInt(std::string(start, len), &parsed_number);
+  bool ok = base::HexStringToInt(start, start + len, &parsed_number);
   if (ok && parsed_number >= 0) {
     *out = parsed_number;
     return true;
   }
   return false;
 }
 
 }  // namespace net