[net/http auth] Use strings to identify authentication schemes.

net/http/http_auth_multi_round_parse.cc

 // Copyright 2015 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 "base/base64.h"
 #include "base/strings/string_util.h"
 #include "net/http/http_auth_challenge_tokenizer.h"
 #include "net/http/http_auth_multi_round_parse.h"
 
 namespace net {
 
-namespace {
-
-// Check that the scheme in the challenge matches the expected scheme
-bool SchemeIsValid(const std::string& scheme,
-                   HttpAuthChallengeTokenizer* challenge) {
-  // There is no guarantee that challenge->scheme() is valid ASCII, but
-  // LowerCaseEqualsASCII will do the right thing even if it isn't.
-  return base::LowerCaseEqualsASCII(challenge->scheme(),
-                                    base::ToLowerASCII(scheme));
-}
-
-}  // namespace
-
 HttpAuth::AuthorizationResult ParseFirstRoundChallenge(
     const std::string& scheme,
     HttpAuthChallengeTokenizer* challenge) {
   // Verify the challenge's auth-scheme.
-  if (!SchemeIsValid(scheme, challenge))
+  if (!challenge->SchemeIs(base::ToLowerASCII(scheme)))
     return HttpAuth::AUTHORIZATION_RESULT_INVALID;
 
   std::string encoded_auth_token = challenge->base64_param();
   if (!encoded_auth_token.empty()) {
     return HttpAuth::AUTHORIZATION_RESULT_INVALID;
   }
   return HttpAuth::AUTHORIZATION_RESULT_ACCEPT;
 }
 
 HttpAuth::AuthorizationResult ParseLaterRoundChallenge(
     const std::string& scheme,
     HttpAuthChallengeTokenizer* challenge,
     std::string* encoded_token,
     std::string* decoded_token) {
   // Verify the challenge's auth-scheme.
-  if (!SchemeIsValid(scheme, challenge))
+  if (!challenge->SchemeIs(base::ToLowerASCII(scheme)))
     return HttpAuth::AUTHORIZATION_RESULT_INVALID;
 
   *encoded_token = challenge->base64_param();
   if (encoded_token->empty())
     return HttpAuth::AUTHORIZATION_RESULT_REJECT;
 
   // Make sure the additional token is base64 encoded.
   if (!base::Base64Decode(*encoded_token, decoded_token))
     return HttpAuth::AUTHORIZATION_RESULT_INVALID;
   return HttpAuth::AUTHORIZATION_RESULT_ACCEPT;
 }
 
 }  // namespace net