Replace base::str[n]casecmp with helper functions.

net/tools/balsa/balsa_headers.h

 // Copyright 2013 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 NET_TOOLS_BALSA_BALSA_HEADERS_H_
 #define NET_TOOLS_BALSA_BALSA_HEADERS_H_
 
 #include <algorithm>
 #include <iosfwd>
 #include <iterator>
@@ skipping 520 matching lines @@
   class const_header_lines_key_iterator : public iterator_base {
     friend class BalsaHeaders;
    public:
     typedef const_header_lines_key_iterator self;
     const_header_lines_key_iterator(const const_header_lines_key_iterator&);
 
     self& operator++() {
       do {
         iterator_base::increment();
       } while (!AtEnd() &&
-               !StringPieceUtils::EqualIgnoreCase(key_, (**this).first));
+               !base::EqualsCaseInsensitiveASCII(key_, (**this).first));
       return *this;
     }
 
     void operator++(int ignore) {
       ++(*this);
     }
 
     // Only forward-iteration makes sense, so no operator-- defined.
 
    private:
@@ skipping 579 matching lines @@
   size_t end_of_firstline_idx_;
 
   bool transfer_encoding_is_chunked_;
 
   HeaderLines header_lines_;
 };
 
 }  // namespace net
 
 #endif  // NET_TOOLS_BALSA_BALSA_HEADERS_H_