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

net/http/http_auth_challenge_tokenizer.cc

Index: net/http/http_auth_challenge_tokenizer.cc
diff --git a/net/http/http_auth_challenge_tokenizer.cc b/net/http/http_auth_challenge_tokenizer.cc
index 75c2d673574bbb9d4743bf620cca5c740892f9d7..65e1b2f25f74454760898f1c3f65e33053c7c69c 100644
--- a/net/http/http_auth_challenge_tokenizer.cc
+++ b/net/http/http_auth_challenge_tokenizer.cc
@@ -5,6 +5,8 @@
 #include "net/http/http_auth_challenge_tokenizer.h"
 
 #include "base/strings/string_tokenizer.h"
+#include "base/strings/string_util.h"
+#include "net/http/http_util.h"
 
 namespace net {
 
@@ -61,4 +63,17 @@ void HttpAuthChallengeTokenizer::Init(std::string::const_iterator begin,
   HttpUtil::TrimLWS(&params_begin_, &params_end_);
 }
 
+std::string HttpAuthChallengeTokenizer::NormalizedScheme() const {
+  if (!HttpUtil::IsToken(scheme_begin_, scheme_end_))
+    return std::string();
+  return base::ToLowerASCII(base::StringPiece(scheme_begin_, scheme_end_));
+}
+
+bool HttpAuthChallengeTokenizer::SchemeIs(
+    const base::StringPiece& scheme) const {
+  DCHECK(base::ToLowerASCII(scheme) == scheme);
+  return base::LowerCaseEqualsASCII(
+      base::StringPiece(scheme_begin_, scheme_end_), scheme);
+}
+
 }  // namespace net