CL here: https://chromium-review.googlesource.com/c/chromium/src/+/1251532

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/979cc8d64a93564438e824ac8d7f986d17fe6092

commit 979cc8d64a93564438e824ac8d7f986d17fe6092
Author: Mario Sanchez Prada <mario@igalia.com>
Date: Fri Sep 28 17:26:22 2018

Migrate DownloadProtectionService to the IdentityManager

Replace instance of SigninManagerBase with one of IdentityManager
and update calls accordingly.

Bug:  889882 
Change-Id: I4e76d223a1b8a6bc328cb97e1624d2c4d7532fae
Reviewed-on: https://chromium-review.googlesource.com/1251532
Reviewed-by: Jialiu Lin <jialiul@chromium.org>
Commit-Queue: Mario Sanchez Prada <mario@igalia.com>
Cr-Commit-Position: refs/heads/master@{#595133}
[modify] https://crrev.com/979cc8d64a93564438e824ac8d7f986d17fe6092/chrome/browser/safe_browsing/download_protection/download_protection_service.cc