autotest: Use dependencies in control file as bot dimensions.

BUG=chromium:873886
TEST=Test on cros-skylab-staging-2.hot.

Change-Id: I50aac9fdeaa5921aa300e340c3082bbae98f831c
Reviewed-on: https://chromium-review.googlesource.com/1180734
Reviewed-by: Xixuan Wu <xixuan@chromium.org>
Commit-Queue: Xixuan Wu <xixuan@chromium.org>
Tested-by: Xixuan Wu <xixuan@chromium.org>
diff --git a/venv/skylab_suite/suite_runner.py b/venv/skylab_suite/suite_runner.py
index 55196f7..968c66c 100644
--- a/venv/skylab_suite/suite_runner.py
+++ b/venv/skylab_suite/suite_runner.py
@@ -306,6 +306,9 @@
                   'label-pool': swarming_lib.SWARMING_DUT_POOL_MAP.get(
                           test_spec.pool),
                   'label-board': test_spec.board}
+    for dependency in test_spec.test.dependencies:
+        # label-tag hasn't been an official label for skylab bots.
+        dimensions['label-tag'] = dependency
 
     osutils = autotest.chromite_load('osutils')
     with osutils.TempDir() as tempdir: