The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/chromite/+/a82d0a22067f72fda9d72c3679f108a9c1550407

commit a82d0a22067f72fda9d72c3679f108a9c1550407
Author: Dhanya Ganesh <dhanyaganesh@chromium.org>
Date: Thu Aug 16 16:16:14 2018

cbuildbot: Create a metric for failing stage

Add an entry into ts_mon/metrics when a build fails to indicate the
failing stage. It should also include the category of stage, so that
an alert can be sent out to the right owner. Some amount of
BuilderStage.Run() code is moved to helper functions.

BUG= chromium:869122 
TEST=tryjob

Change-Id: I50cce5473601397a6abeb10723eef77169e5a0b5
Reviewed-on: https://chromium-review.googlesource.com/1155705
Commit-Ready: Dhanya Ganesh <dhanyaganesh@chromium.org>
Tested-by: Dhanya Ganesh <dhanyaganesh@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>

[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/android_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/generic_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/branch_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/builders/generic_builders.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/report_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/tast_test_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/sdk_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/lib/results_lib_unittest.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/release_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/vm_test_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/infra_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/test_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/build_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/artifact_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/lib/failures_lib.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/scheduler_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/completion_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/workspace_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/alert_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/chrome_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/afdo_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/sync_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/config_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/cbuildbot/stages/handle_changes_stages.py
[modify] https://crrev.com/a82d0a22067f72fda9d72c3679f108a9c1550407/lib/constants.py