The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra/+/5d3a96ade45b7685b571af650d46159c1d942e36

commit 5d3a96ade45b7685b571af650d46159c1d942e36
Author: Chan <chanli@chromium.org>
Date: Thu Jul 26 17:33:31 2018

[Findit] add canonical_step_name and isolate_target_name to metrics for trigged flake anlayses.

These metrics could help us to know the number of analyses for different test types.

Bug:  865737 
Change-Id: Ife2dcb1bca49ecbc00152844fc0347aa91307780
Reviewed-on: https://chromium-review.googlesource.com/1144309
Commit-Queue: Chan Li <chanli@chromium.org>
Reviewed-by: Jeffrey Li <lijeffrey@chromium.org>
Reviewed-by: Roberto Carrillo <robertocn@chromium.org>

[modify] https://crrev.com/5d3a96ade45b7685b571af650d46159c1d942e36/appengine/findit/waterfall/flake/step_mapper.py
[modify] https://crrev.com/5d3a96ade45b7685b571af650d46159c1d942e36/appengine/findit/services/test/monitoring_test.py
[modify] https://crrev.com/5d3a96ade45b7685b571af650d46159c1d942e36/appengine/findit/common/monitoring.py
[modify] https://crrev.com/5d3a96ade45b7685b571af650d46159c1d942e36/appengine/findit/waterfall/flake/test/flake_analysis_service_test.py
[modify] https://crrev.com/5d3a96ade45b7685b571af650d46159c1d942e36/appengine/findit/model/flake/flake_analysis_request.py
[modify] https://crrev.com/5d3a96ade45b7685b571af650d46159c1d942e36/appengine/findit/waterfall/flake/flake_analysis_service.py
[modify] https://crrev.com/5d3a96ade45b7685b571af650d46159c1d942e36/appengine/findit/services/monitoring.py