Linux has been done by tangltom with crrev.com/c/704937

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/39c08fc9cc0fa14f7e63d3d1fe784661220def13

commit 39c08fc9cc0fa14f7e63d3d1fe784661220def13
Author: Jérôme Lebel <jlebel@chromium.org>
Date: Tue Oct 17 23:34:19 2017

Removing dead code in profile_chooser_controller.mm

Removing switch user mode ProfileChooserController, with all strings and
resources related.

Linux/Windows cleanup done previously in: crrev.com/c/704937

User switch feature was added: crrev.com/435423005

Bug:  775110 
Change-Id: I6de5e8d8875402d4aaa347f32213440c35f779c5
Reviewed-on: https://chromium-review.googlesource.com/706776
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Ilya Sherman <isherman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#509593}
[modify] https://crrev.com/39c08fc9cc0fa14f7e63d3d1fe784661220def13/chrome/app/chromium_strings.grd
[modify] https://crrev.com/39c08fc9cc0fa14f7e63d3d1fe784661220def13/chrome/app/generated_resources.grd
[modify] https://crrev.com/39c08fc9cc0fa14f7e63d3d1fe784661220def13/chrome/app/google_chrome_strings.grd
[delete] https://crrev.com/269c8ebdce06f2df62be0cec2cd2820ef4183e80/chrome/app/theme/default_100_percent/legacy/avatar_menu_disconnect.png
[delete] https://crrev.com/269c8ebdce06f2df62be0cec2cd2820ef4183e80/chrome/app/theme/default_100_percent/legacy/avatar_menu_profile.png
[delete] https://crrev.com/269c8ebdce06f2df62be0cec2cd2820ef4183e80/chrome/app/theme/default_100_percent/legacy/edit_button_hover.png
[delete] https://crrev.com/269c8ebdce06f2df62be0cec2cd2820ef4183e80/chrome/app/theme/default_100_percent/legacy/edit_button_pressed.png
[delete] https://crrev.com/269c8ebdce06f2df62be0cec2cd2820ef4183e80/chrome/app/theme/default_100_percent/legacy/edit_camera.png
[delete] https://crrev.com/269c8ebdce06f2df62be0cec2cd2820ef4183e80/chrome/app/theme/default_200_percent/legacy/avatar_menu_disconnect.png
[delete] https://crrev.com/269c8ebdce06f2df62be0cec2cd2820ef4183e80/chrome/app/theme/default_200_percent/legacy/avatar_menu_profile.png
[delete] https://crrev.com/269c8ebdce06f2df62be0cec2cd2820ef4183e80/chrome/app/theme/default_200_percent/legacy/edit_button_hover.png
[delete] https://crrev.com/269c8ebdce06f2df62be0cec2cd2820ef4183e80/chrome/app/theme/default_200_percent/legacy/edit_button_pressed.png
[delete] https://crrev.com/269c8ebdce06f2df62be0cec2cd2820ef4183e80/chrome/app/theme/default_200_percent/legacy/edit_camera.png
[modify] https://crrev.com/39c08fc9cc0fa14f7e63d3d1fe784661220def13/chrome/app/theme/theme_resources.grd
[modify] https://crrev.com/39c08fc9cc0fa14f7e63d3d1fe784661220def13/chrome/browser/profiles/profile_metrics.cc
[modify] https://crrev.com/39c08fc9cc0fa14f7e63d3d1fe784661220def13/chrome/browser/profiles/profile_metrics.h
[modify] https://crrev.com/39c08fc9cc0fa14f7e63d3d1fe784661220def13/chrome/browser/ui/cocoa/profiles/profile_chooser_controller.mm
[modify] https://crrev.com/39c08fc9cc0fa14f7e63d3d1fe784661220def13/chrome/browser/ui/profile_chooser_constants.h
[modify] https://crrev.com/39c08fc9cc0fa14f7e63d3d1fe784661220def13/chrome/browser/ui/views/profiles/profile_chooser_view.cc
[modify] https://crrev.com/39c08fc9cc0fa14f7e63d3d1fe784661220def13/tools/metrics/histograms/histograms.xml