Taking this one. CL here:
https://chromium-review.googlesource.com/c/chromium/src/+/1380091

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/09107ed657a687beb8e239ba5d0a648cc15bdbe6

commit 09107ed657a687beb8e239ba5d0a648cc15bdbe6
Author: Mario Sanchez Prada <mario@igalia.com>
Date: Tue Dec 18 15:04:35 2018

Convert metrics to use Identity Service client library

At this point, this means converting the usage of SigninManagerBase API
in ukm_browsertest.cc, depend on the right factory (IdentityManagerFactory)
from DesktopProfileSessionDurationsServiceFactory and remove stale includes.

Bug:  797886 
Change-Id: Ib5861095f0265de71aa1e58cb37895991420dc85
Reviewed-on: https://chromium-review.googlesource.com/c/1380091
Reviewed-by: Colin Blundell <blundell@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Commit-Queue: Mario Sanchez Prada <mario@igalia.com>
Cr-Commit-Position: refs/heads/master@{#617493}
[modify] https://crrev.com/09107ed657a687beb8e239ba5d0a648cc15bdbe6/chrome/browser/metrics/ukm_browsertest.cc