dependency: List endpoint return reverse dependencies.

Have the List endpoint return reverse dependencies by default. Currently
the only use case of the endpoint is slim builds.

BUG=chromium:1149921, b:178484769
TEST=./run_pytest

Change-Id: I3f6a736a7b729493474a302ac729000cbd8d4339
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2775290
Tested-by: Navil Perez <navil@google.com>
Reviewed-by: Michael Mortensen <mmortensen@google.com>
Commit-Queue: Navil Perez <navil@google.com>
diff --git a/api/controller/dependency_unittest.py b/api/controller/dependency_unittest.py
index f1f44af..36e1ffa 100644
--- a/api/controller/dependency_unittest.py
+++ b/api/controller/dependency_unittest.py
@@ -210,6 +210,9 @@
         packages=[input_package_info_proto])
     dependency.List(input_proto, self.response, self.api_config)
     mock_get_deps.assert_called_once_with(
-        self.sysroot, src_paths=[path], packages=[input_package_info])
+        self.sysroot,
+        src_paths=[path],
+        packages=[input_package_info],
+        include_rev_dependencies=True)
     self.assertCountEqual([return_package_info_proto],
                           self.response.package_deps)