Support specifying the GSSAPI library that will be used.

net/http/http_auth_handler_negotiate.cc

Index: net/http/http_auth_handler_negotiate.cc
diff --git a/net/http/http_auth_handler_negotiate.cc b/net/http/http_auth_handler_negotiate.cc
index 99abdf6cb941a74314f7ea1ba52d9d58c62d3737..2c59f7ddfa4f30d4d5f6f27fe40d97fd916577b3 100644
--- a/net/http/http_auth_handler_negotiate.cc
+++ b/net/http/http_auth_handler_negotiate.cc
@@ -276,7 +276,7 @@ HttpAuthHandlerNegotiate::Factory::Factory()
       is_unsupported_(false),
       auth_library_(SSPILibrary::GetDefault()) {
 #elif defined(OS_POSIX)
-      auth_library_(GSSAPILibrary::GetDefault()) {
+      auth_library_(NULL) {
 #endif
 }
 
@@ -310,7 +310,7 @@ int HttpAuthHandlerNegotiate::Factory::CreateAuthHandler(
   // TODO(cbentzel): Move towards model of parsing in the factory
   //                 method and only constructing when valid.
   scoped_ptr<HttpAuthHandler> tmp_handler(
-      new HttpAuthHandlerNegotiate(auth_library_, max_token_length_,
+      new HttpAuthHandlerNegotiate(auth_library_.get(), max_token_length_,
                                    url_security_manager(), resolver_,
                                    disable_cname_lookup_, use_port_));
   if (!tmp_handler->InitFromChallenge(challenge, target, origin, net_log))
@@ -321,7 +321,7 @@ int HttpAuthHandlerNegotiate::Factory::CreateAuthHandler(
   // TODO(ahendrickson): Move towards model of parsing in the factory
   //                     method and only constructing when valid.
   scoped_ptr<HttpAuthHandler> tmp_handler(
-      new HttpAuthHandlerNegotiate(auth_library_, url_security_manager(),
+      new HttpAuthHandlerNegotiate(auth_library_.get(), url_security_manager(),
                                    resolver_, disable_cname_lookup_,
                                    use_port_));
   if (!tmp_handler->InitFromChallenge(challenge, target, origin, net_log))