Advertise transport selected in user-agent string
diff --git a/test/core/channel/channel_stack_test.c b/test/core/channel/channel_stack_test.c
index 1a5594b..2d7737a 100644
--- a/test/core/channel/channel_stack_test.c
+++ b/test/core/channel/channel_stack_test.c
@@ -123,7 +123,7 @@
channel_stack = gpr_malloc(grpc_channel_stack_size(&filters, 1));
grpc_channel_stack_init(&exec_ctx, 1, free_channel, channel_stack, &filters,
- 1, &chan_args, "test", channel_stack);
+ 1, &chan_args, NULL, "test", channel_stack);
GPR_ASSERT(channel_stack->count == 1);
channel_elem = grpc_channel_stack_element(channel_stack, 0);
channel_data = (int *)channel_elem->channel_data;