Assigning to me

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0185ed4dda6ac1f30e830925131e45f796c04a8e

commit 0185ed4dda6ac1f30e830925131e45f796c04a8e
Author: Sergio Villar Senin <svillar@igalia.com>
Date: Tue Jan 22 18:16:01 2019

Remove leftover SigninManager include from signin_utils_desktop.cc

The whole file but the SigninManager include, was migrated to
IdentityManager in crrev.com/c/1354198 .

Bug: 920244
Change-Id: I142be4dd2a2c295a8128d9293f52680be44e358d
Reviewed-on: https://chromium-review.googlesource.com/c/1407195
Reviewed-by: Roger Tawa <rogerta@chromium.org>
Commit-Queue: Sergio Villar <svillar@igalia.com>
Cr-Commit-Position: refs/heads/master@{#624834}
[modify] https://crrev.com/0185ed4dda6ac1f30e830925131e45f796c04a8e/chrome/browser/ui/webui/signin/signin_utils_desktop.cc