https://findit-for-me.appspot.com/waterfall/check-flake?master_name=chromium.linux&builder_name=Linux%20Tests&build_number=49797&step_name=gfx_unittests&test_name=virtual/mojo-loading/http/tests/serviceworker/chromium/register-error-messages.html

Chromium-try-flake report the flaky test with a different step name. One investigation is in  bug 673898 .

Workaround: check whether test exists (enabled + disabled) or not. If chromium-try-flakes reports a flaky test with a wrong step name, then the test won't be in the result of that step.

The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra.git/+/1a1cac9c5b2a7c5a6709cf7fbd110d4b25baf20a

commit 1a1cac9c5b2a7c5a6709cf7fbd110d4b25baf20a
Author: Shuotao Gao <stgao@chromium.org>
Date: Wed Dec 14 00:23:36 2016

[Findit] Check whether test exists to workaround wrong step name from flake report.

BUG= 672720 
R=chanli, lijeffrey

Change-Id: I95e6a4cb5e6e8da3a14fedcb8ea0dc039364a79a
Reviewed-on: https://chromium-review.googlesource.com/419839
Reviewed-by: Jeffrey Li <lijeffrey@chromium.org>
Reviewed-by: Chan Li <chanli@chromium.org>
Commit-Queue: Shuotao Gao <stgao@chromium.org>

[modify] https://crrev.com/1a1cac9c5b2a7c5a6709cf7fbd110d4b25baf20a/appengine/findit/waterfall/flake/flake_analysis_service.py
[modify] https://crrev.com/1a1cac9c5b2a7c5a6709cf7fbd110d4b25baf20a/appengine/findit/waterfall/flake/step_mapper.py