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

net/http/http_request_headers.cc

 // Copyright (c) 2012 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.
 
 #include "net/http/http_request_headers.h"
 
 #include "base/logging.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
@@ skipping 223 matching lines @@
     }
     headers->AddHeaderFromString(header_line);
   }
   return true;
 }
 
 HttpRequestHeaders::HeaderVector::iterator
 HttpRequestHeaders::FindHeader(const base::StringPiece& key) {
   for (HeaderVector::iterator it = headers_.begin();
        it != headers_.end(); ++it) {
-    if (key.length() == it->key.length() &&
-        !base::strncasecmp(key.data(), it->key.data(), key.length()))
+    if (base::EqualsCaseInsensitiveASCII(key, it->key))
       return it;
   }
 
   return headers_.end();
 }
 
 HttpRequestHeaders::HeaderVector::const_iterator
 HttpRequestHeaders::FindHeader(const base::StringPiece& key) const {
   for (HeaderVector::const_iterator it = headers_.begin();
        it != headers_.end(); ++it) {
-    if (key.length() == it->key.length() &&
-        !base::strncasecmp(key.data(), it->key.data(), key.length()))
+    if (base::EqualsCaseInsensitiveASCII(key, it->key))
       return it;
   }
 
   return headers_.end();
 }
 
 }  // namespace net