Enable loading gssapi library for Chromad.

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 e957676fc40be1c30e7df5ca46b45b4b25d77985..afe8c008b2be1d3c3d05da91d0a763439dcb0d80 100644
--- a/net/http/http_auth_handler_negotiate.cc
+++ b/net/http/http_auth_handler_negotiate.cc
@@ -92,7 +92,12 @@ int HttpAuthHandlerNegotiate::Factory::CreateAuthHandler(
   std::unique_ptr<HttpAuthHandler> tmp_handler(
       new HttpAuthHandlerNegotiate(http_auth_preferences(), resolver_));
 #elif defined(OS_POSIX)
-  if (is_unsupported_)
+  bool allow_gssapi_library_load = true;
+#if defined(OS_CHROMEOS)
+  allow_gssapi_library_load = http_auth_preferences() &&
+                              http_auth_preferences()->AllowGssapiLibraryLoad();
+#endif
+  if (is_unsupported_ || !allow_gssapi_library_load)
     return ERR_UNSUPPORTED_AUTH_SCHEME;
   if (!auth_library_->Init()) {
     is_unsupported_ = true;