The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra/+/b0f8ad63f25d90b8c683072f316969c660c38b86

commit b0f8ad63f25d90b8c683072f316969c660c38b86
Author: Jeffrey Li <lijeffrey@chromium.org>
Date: Wed Jan 31 00:25:09 2018

[Findit] Flake Analyzer - New DetermineApproximatePassRatePipeline

1. Refactored waterfall/flake/determine_true_pass_rate_pipeline.py into new pipelines/flake_failure/determine_approximate_pass_rate_pipeline.py.
   Original: https://chromium.googlesource.com/infra/infra/+/master/appengine/findit/waterfall/flake/determine_true_pass_rate_pipeline.py
2. Created services/flake_failure/pass_rate_util.py to handle all operations on pass rates.
3. Created services/flake_failure/run_swarming_util.py to handle all operations on calculating parameters to send to swarming tasks.
4. Created services/flake_failure/data_point_util.py to handle all DataPoint-related operations.
5. Deprecates FlakeSwarmingTask
6. Move logic for counting errors in swarming task to per-data point level rather than analysis level

Bug:  799566 
Change-Id: Ic2a3c37d5458b24b2eabc50e4bf048e2953b87d4
Reviewed-on: https://chromium-review.googlesource.com/882462
Commit-Queue: Jeffrey Li <lijeffrey@chromium.org>
Reviewed-by: Shuotao Gao <stgao@chromium.org>
Reviewed-by: Brandon Wylie <wylieb@chromium.org>

[modify] https://crrev.com/b0f8ad63f25d90b8c683072f316969c660c38b86/appengine/findit/pipelines/flake_failure/run_flake_try_job_pipeline.py
[add] https://crrev.com/b0f8ad63f25d90b8c683072f316969c660c38b86/appengine/findit/services/flake_failure/pass_rate_util.py
[add] https://crrev.com/b0f8ad63f25d90b8c683072f316969c660c38b86/appengine/findit/services/flake_failure/run_swarming_util.py
[add] https://crrev.com/b0f8ad63f25d90b8c683072f316969c660c38b86/appengine/findit/services/flake_failure/test/run_swarming_util_test.py
[modify] https://crrev.com/b0f8ad63f25d90b8c683072f316969c660c38b86/appengine/findit/services/flake_failure/lookback_algorithm.py
[add] https://crrev.com/b0f8ad63f25d90b8c683072f316969c660c38b86/appengine/findit/pipelines/flake_failure/run_flake_swarming_task_pipeline.py
[add] https://crrev.com/b0f8ad63f25d90b8c683072f316969c660c38b86/appengine/findit/services/flake_failure/data_point_util.py
[add] https://crrev.com/b0f8ad63f25d90b8c683072f316969c660c38b86/appengine/findit/services/flake_failure/test/data_point_util_test.py
[modify] https://crrev.com/b0f8ad63f25d90b8c683072f316969c660c38b86/appengine/findit/model/flake/master_flake_analysis.py
[modify] https://crrev.com/b0f8ad63f25d90b8c683072f316969c660c38b86/appengine/findit/waterfall/flake/flake_constants.py
[add] https://crrev.com/b0f8ad63f25d90b8c683072f316969c660c38b86/appengine/findit/dto/swarming_task_error.py
[add] https://crrev.com/b0f8ad63f25d90b8c683072f316969c660c38b86/appengine/findit/pipelines/flake_failure/determine_approximate_pass_rate_pipeline.py
[add] https://crrev.com/b0f8ad63f25d90b8c683072f316969c660c38b86/appengine/findit/services/flake_failure/test/pass_rate_util_test.py
[add] https://crrev.com/b0f8ad63f25d90b8c683072f316969c660c38b86/appengine/findit/pipelines/flake_failure/test/determine_approximate_pass_rate_pipeline_test.py