[Findit] Refactor Findit pipeline.

appengine/findit/waterfall/analyze_build_failure_pipeline.py

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 from datetime import datetime
 
 from common import appengine_util
 from common.pipeline_wrapper import BasePipeline
 from common.pipeline_wrapper import pipeline
 from model import analysis_status
@@ skipping 52 matching lines @@
     analysis.put()
 
   # Arguments number differs from overridden method - pylint: disable=W0221
   def run(self, master_name, builder_name, build_number, build_completed,
           force_rerun_try_job):
     self._ResetAnalysis(master_name, builder_name, build_number)
 
     # The yield statements below return PipelineFutures, which allow subsequent
     # pipelines to refer to previous output values.
     # https://github.com/GoogleCloudPlatform/appengine-pipelines/wiki/Python
+
+    # Heuristic Approach.
     failure_info = yield DetectFirstFailurePipeline(
         master_name, builder_name, build_number)
     change_logs = yield PullChangelogPipeline(failure_info)
     deps_info = yield ExtractDEPSInfoPipeline(failure_info, change_logs)
     signals = yield ExtractSignalPipeline(failure_info)
     heuristic_result = yield IdentifyCulpritPipeline(
         failure_info, change_logs, deps_info, signals, build_completed)
 
+    # Try job Approach.
     with pipeline.InOrder():
-      # Triggers swarming tasks when test failure happens.
+      # Swarming rerun.
+      # Triggers swarming tasks when first time test failure happens.
+      # This pipeline will run before build completes.
       yield TriggerSwarmingTasksPipeline(
           master_name, builder_name, build_number, failure_info)
-      # Checks if need a try job and starts one if yes.
+      # Checks if first time failures happen and starts a try job if yes.
       yield StartTryJobOnDemandPipeline(
-          failure_info, signals, build_completed, force_rerun_try_job,
-          heuristic_result)
+          master_name, builder_name, build_number, failure_info,
+          signals, heuristic_result, build_completed, force_rerun_try_job)