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

net/http/http_auth_handler_factory.h

Index: net/http/http_auth_handler_factory.h
diff --git a/net/http/http_auth_handler_factory.h b/net/http/http_auth_handler_factory.h
index 1261bedd567645f3e6c5fc3a5e214f2652569297..c068932fac982634d38ed7db51f648e98b74b667 100644
--- a/net/http/http_auth_handler_factory.h
+++ b/net/http/http_auth_handler_factory.h
@@ -188,8 +188,8 @@ class NET_EXPORT HttpAuthHandlerRegistryFactory
       bool negotiate_disable_cname_lookup,
       bool negotiate_enable_port);
 
-  // Creates an auth handler by dispatching out to the registered factories
-  // based on the first token in |challenge|.
+  // Create an auth handler by dispatching the CreateAuthHandler() call to the
+  // factory registered to handle challenge->scheme().
   int CreateAuthHandler(HttpAuthChallengeTokenizer* challenge,
                         HttpAuth::Target target,
                         const GURL& origin,