The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/chromite/+/8beb534a594f59d4fd4afad5123dba97960f9f16

commit 8beb534a594f59d4fd4afad5123dba97960f9f16
Author: Ningning Xia <nxia@chromium.org>
Date: Fri Feb 10 04:48:46 2017

Update SlaveStatus.builders_array given the scheduled builds in metadata

Previously SlaveStatus.builders_array was a list of slave build configs
got by parsing the config files. CQ-master now records scheduled slave
builds in metadata. It's possible that CQ-master has a list of
imporatant slaves configured but it doesn't schedule any slaves as
there's no CL to test. SlaveStatus should handle the logic correctly by
updating the builders_array (list of expected slave builds) to the list
of scheduled builds recorded in metadata.

BUG= chromium:690258 
TEST=unit_tests

Change-Id: I412da7618d354137b44f4238a05ec0fcd2ef31a7
Reviewed-on: https://chromium-review.googlesource.com/439786
Commit-Ready: Ningning Xia <nxia@chromium.org>
Tested-by: Ningning Xia <nxia@chromium.org>
Reviewed-by: Ningning Xia <nxia@chromium.org>

[modify] https://crrev.com/8beb534a594f59d4fd4afad5123dba97960f9f16/cbuildbot/build_status_unittest.py
[modify] https://crrev.com/8beb534a594f59d4fd4afad5123dba97960f9f16/cbuildbot/build_status.py
[modify] https://crrev.com/8beb534a594f59d4fd4afad5123dba97960f9f16/cbuildbot/manifest_version_unittest.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/chromite/+/c6c12bf1e91c0914fdca1dd0f5ab75848c43939b

commit c6c12bf1e91c0914fdca1dd0f5ab75848c43939b
Author: Ningning Xia <nxia@chromium.org>
Date: Sat Feb 11 08:35:22 2017

Do not schedule CQ slaves when there's no new or chump CL.

When there're only chump CLs in a CQ run, we should still trigger slave
builds to verify the blamelist (chump CLs in this case).

BUG= chromium:690258 
TEST=unit_tests

Change-Id: Ieb2eca071b3be0d7f66f721cce0a859f352d1988
Reviewed-on: https://chromium-review.googlesource.com/440147
Commit-Ready: Ningning Xia <nxia@chromium.org>
Tested-by: Ningning Xia <nxia@chromium.org>
Reviewed-by: Ningning Xia <nxia@chromium.org>

[modify] https://crrev.com/c6c12bf1e91c0914fdca1dd0f5ab75848c43939b/cbuildbot/stages/scheduler_stages.py
[modify] https://crrev.com/c6c12bf1e91c0914fdca1dd0f5ab75848c43939b/cbuildbot/validation_pool.py
[modify] https://crrev.com/c6c12bf1e91c0914fdca1dd0f5ab75848c43939b/cbuildbot/lkgm_manager_unittest.py
[modify] https://crrev.com/c6c12bf1e91c0914fdca1dd0f5ab75848c43939b/cbuildbot/lkgm_manager.py
[modify] https://crrev.com/c6c12bf1e91c0914fdca1dd0f5ab75848c43939b/cbuildbot/stages/scheduler_stages_unittest.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/chromite/+/63394e2563047f97b2293569cf5f6495cdce3215

commit 63394e2563047f97b2293569cf5f6495cdce3215
Author: Ningning Xia <nxia@chromium.org>
Date: Sat Feb 25 12:19:52 2017

Do not mark CQ-master Completion stage as fail when no CL is picked up.

When no CL is picked up by sync_stage.validation_pool, no CQ slaves are
scheduled by CQ-master. Return False _IsFailureFatal when CQ-master
hasn't scheduled any slaves and so do not mark CQ-master completion
stage as fail.

BUG= chromium:690258 
TEST=unit_tests

Change-Id: I37656f605f432437dd8a362ee5baf6a990a8f9a9
Reviewed-on: https://chromium-review.googlesource.com/441944
Commit-Ready: Ningning Xia <nxia@chromium.org>
Tested-by: Ningning Xia <nxia@chromium.org>
Reviewed-by: Ningning Xia <nxia@chromium.org>

[modify] https://crrev.com/63394e2563047f97b2293569cf5f6495cdce3215/cbuildbot/stages/scheduler_stages.py
[modify] https://crrev.com/63394e2563047f97b2293569cf5f6495cdce3215/cbuildbot/validation_pool.py
[modify] https://crrev.com/63394e2563047f97b2293569cf5f6495cdce3215/cbuildbot/stages/scheduler_stages_unittest.py
[modify] https://crrev.com/63394e2563047f97b2293569cf5f6495cdce3215/cbuildbot/validation_pool_unittest.py
[modify] https://crrev.com/63394e2563047f97b2293569cf5f6495cdce3215/cbuildbot/stages/completion_stages.py
[modify] https://crrev.com/63394e2563047f97b2293569cf5f6495cdce3215/cbuildbot/stages/completion_stages_unittest.py