api/router: Add support for hidden services/methods.

BUG=None
TEST=./run_pytest

Cq-Depend: chromium:2728532
Change-Id: I72e57fa74f9ea2cb0044228553d3b6b248b76262
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2729182
Tested-by: Alex Klein <saklein@chromium.org>
Reviewed-by: LaMont Jones <lamontjones@chromium.org>
Commit-Queue: Alex Klein <saklein@chromium.org>
diff --git a/api/router_unittest.py b/api/router_unittest.py
index 32942f9..69bfccd 100644
--- a/api/router_unittest.py
+++ b/api/router_unittest.py
@@ -380,3 +380,12 @@
       self.router.Route(service, method, self.api_config,
                         self.binary_input_handler, [self.binary_output_handler],
                         self.binary_config_handler)
+
+  def testListVisibility(self):
+    """Test visibility options."""
+    service = 'HiddenService'
+    method = 'HiddenMethod'
+
+    for current in self.router.ListMethods():
+      self.assertNotIn(service, current)
+      self.assertNotIn(method, current)