The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra/+/8b09a40c6d97882eddeec51a450ef04bed5254ec

commit 8b09a40c6d97882eddeec51a450ef04bed5254ec
Author: Jeffrey Li <lijeffrey@chromium.org>
Date: Fri Sep 29 07:43:36 2017

[Findit] Flake Analyzer - Hook up suspected CLs to try jobs

1. Suspected CLs are in the form 'r1', 'r3', etc.
2. Suspected CLs are represented as ranges [(None, 'r1'), ('r2, 'r3')] where
   the first value in each tuple is the revision right before the suspect.
   The goal is to run a try job on the previous suspect to confirm its
   stability, then the suspect itself to confirm its flakiness.
3. Convert [(None, 'r1'), ('r2, 'r3)] to a flattend list of their corresponding
   commit positions, e.g. [1, 2, 3].
4. Pass [1, 2, 3] to the try job pipelines, with NextCommitPositionPipeline simply
   returning the next value in the list.
5. Even if all values are attempted and no suspect is identified, the data points
   generated as a side effect can still assist bisect in where to find the latest
   stable build point to treat as the lower bound for bisecting the remainder of the
   range.

Bug:  735533 
Change-Id: I9461ca468497e2c5df2d335ac3ab25444abd6f04
Reviewed-on: https://chromium-review.googlesource.com/668136
Commit-Queue: Jeffrey Li <lijeffrey@chromium.org>
Reviewed-by: Shuotao Gao <stgao@chromium.org>
Reviewed-by: Brandon Wylie <wylieb@chromium.org>
Reviewed-by: Roberto Carrillo <robertocn@chromium.org>

[modify] https://crrev.com/8b09a40c6d97882eddeec51a450ef04bed5254ec/appengine/findit/waterfall/flake/initialize_flake_try_job_pipeline.py
[modify] https://crrev.com/8b09a40c6d97882eddeec51a450ef04bed5254ec/appengine/findit/waterfall/flake/test/initialize_flake_try_job_pipeline_test.py
[modify] https://crrev.com/8b09a40c6d97882eddeec51a450ef04bed5254ec/appengine/findit/waterfall/flake/recursive_flake_try_job_pipeline.py
[modify] https://crrev.com/8b09a40c6d97882eddeec51a450ef04bed5254ec/appengine/findit/waterfall/flake/test/recursive_flake_try_job_pipeline_test.py
[modify] https://crrev.com/8b09a40c6d97882eddeec51a450ef04bed5254ec/appengine/findit/waterfall/flake/test/finish_build_analysis_pipeline_test.py
[modify] https://crrev.com/8b09a40c6d97882eddeec51a450ef04bed5254ec/appengine/findit/waterfall/flake/heuristic_analysis_util.py
[modify] https://crrev.com/8b09a40c6d97882eddeec51a450ef04bed5254ec/appengine/findit/waterfall/flake/finish_build_analysis_pipeline.py
[modify] https://crrev.com/8b09a40c6d97882eddeec51a450ef04bed5254ec/appengine/findit/waterfall/flake/test/heuristic_analysis_util_test.py
[modify] https://crrev.com/8b09a40c6d97882eddeec51a450ef04bed5254ec/appengine/findit/waterfall/flake/identify_suspected_revisions_pipeline.py