MonitoredDomainGroupId in components/password_manager/core/browser/password_manager_metrics_util.cc has been broken for some time (attempting to create a GURL from only a host, which resulted in an empty GURL), so the reporting of histograms like PasswordManager.ProvisionalSaveFailure_group_1 has not been working for quite some time.
Nobody noticed this, because sadly these histograms were not looked at. They were initially an attempt to allow us monitor password manager breakages on interesting sites while preserving user privacy [1], but the approach does not scale beyond a handful of sites, and we went with other ways of monitoring in the meantime.
Therefore, the related code should be removed, to simplify the code and get rid of unused preferences.
[1] https://docs.google.com/document/d/1mhg3fP44tG9GyZraBoKwzW_RzX27jm9vo91Z86OlXwg/edit?usp=sharing
Comment 1 by bugdroid1@chromium.org
, Mar 9 2016