Before merging pipelines, first we need to separate logic from pipelines.

The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra/+/311fa3906acc03dbbec5c2a03b8186882d727616

commit 311fa3906acc03dbbec5c2a03b8186882d727616
Author: Chan <chanli@chromium.org>
Date: Fri Aug 25 21:40:09 2017

[Findit] Separate logic of extract deps info to a service module.

Bug:  757667 
Change-Id: I5f53f0e0c586bed786fde91d8358b7084561c2d8
Reviewed-on: https://chromium-review.googlesource.com/630383
Commit-Queue: Chan Li <chanli@chromium.org>
Reviewed-by: Jeffrey Li <lijeffrey@chromium.org>
Reviewed-by: Shuotao Gao <stgao@chromium.org>

[modify] https://crrev.com/311fa3906acc03dbbec5c2a03b8186882d727616/appengine/findit/waterfall/test/extract_deps_info_pipeline_test.py
[add] https://crrev.com/311fa3906acc03dbbec5c2a03b8186882d727616/appengine/findit/services/deps.py
[add] https://crrev.com/311fa3906acc03dbbec5c2a03b8186882d727616/appengine/findit/services/test/__init__.py
[add] https://crrev.com/311fa3906acc03dbbec5c2a03b8186882d727616/appengine/findit/services/test/deps_test.py
[modify] https://crrev.com/311fa3906acc03dbbec5c2a03b8186882d727616/appengine/findit/waterfall/extract_deps_info_pipeline.py

The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra/+/23ac7e9755d670f8a707461a316f3358ce513c77

commit 23ac7e9755d670f8a707461a316f3358ce513c77
Author: Chan <chanli@chromium.org>
Date: Fri Aug 25 22:23:29 2017

[Findit] Move logic in identify_culprit_pipeline to build_failure_analysis.py

Bug:  757667 
Change-Id: I9c3e7f4a112ed41fe14dad5a0b4e8c0442459f3f
Reviewed-on: https://chromium-review.googlesource.com/634526
Reviewed-by: Shuotao Gao <stgao@chromium.org>
Commit-Queue: Chan Li <chanli@chromium.org>

[modify] https://crrev.com/23ac7e9755d670f8a707461a316f3358ce513c77/appengine/findit/waterfall/test/build_failure_analysis_test.py
[modify] https://crrev.com/23ac7e9755d670f8a707461a316f3358ce513c77/appengine/findit/handlers/test/list_analyses_test.py
[modify] https://crrev.com/23ac7e9755d670f8a707461a316f3358ce513c77/appengine/findit/waterfall/test/identify_culprit_pipeline_test.py
[modify] https://crrev.com/23ac7e9755d670f8a707461a316f3358ce513c77/appengine/findit/waterfall/build_failure_analysis.py
[modify] https://crrev.com/23ac7e9755d670f8a707461a316f3358ce513c77/appengine/findit/waterfall/identify_culprit_pipeline.py

The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra/+/96990e4e17768932817128ac955eb5754c5cdce3

commit 96990e4e17768932817128ac955eb5754c5cdce3
Author: Chan <chanli@chromium.org>
Date: Tue Aug 29 18:09:02 2017

[Findit] Merge pipelines.

Merge PullChangeLogPipeline and ExtractDepsInfoPipeline into IdentifyCulpritPipeline.

Bug:  757667 
Change-Id: I67705859144b23c3dbacd50eae1860a1ef15e51a
Reviewed-on: https://chromium-review.googlesource.com/636301
Commit-Queue: Chan Li <chanli@chromium.org>
Reviewed-by: Shuotao Gao <stgao@chromium.org>

[modify] https://crrev.com/96990e4e17768932817128ac955eb5754c5cdce3/appengine/findit/waterfall/test/build_failure_analysis_test.py
[delete] https://crrev.com/73df5c9cc0d0a66a7e84d3b97085e62ec1085f58/appengine/findit/waterfall/test/extract_deps_info_pipeline_test.py
[delete] https://crrev.com/73df5c9cc0d0a66a7e84d3b97085e62ec1085f58/appengine/findit/waterfall/test/pull_changelog_pipeline_test.py
[modify] https://crrev.com/96990e4e17768932817128ac955eb5754c5cdce3/appengine/findit/waterfall/test/identify_culprit_pipeline_test.py
[modify] https://crrev.com/96990e4e17768932817128ac955eb5754c5cdce3/appengine/findit/waterfall/test/analyze_build_failure_pipeline_test.py
[delete] https://crrev.com/73df5c9cc0d0a66a7e84d3b97085e62ec1085f58/appengine/findit/waterfall/extract_deps_info_pipeline.py
[delete] https://crrev.com/73df5c9cc0d0a66a7e84d3b97085e62ec1085f58/appengine/findit/waterfall/pull_changelog_pipeline.py
[modify] https://crrev.com/96990e4e17768932817128ac955eb5754c5cdce3/appengine/findit/waterfall/analyze_build_failure_pipeline.py
[modify] https://crrev.com/96990e4e17768932817128ac955eb5754c5cdce3/appengine/findit/waterfall/identify_culprit_pipeline.py
[modify] https://crrev.com/96990e4e17768932817128ac955eb5754c5cdce3/appengine/findit/waterfall/build_failure_analysis.py