ewald@ Do you feel this should be done only with the ctrl+shift+m? Or should it be done always when clicking on the button?
I've implemented that on macOS, and I see the focus contour which is unusual.

Jerome and I chatted offline. We're going to just implement the behavior described in the original bug description for now and investigate further improvements offline.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/eb2e0d02e494c55d5e3721fe8a70f2e4f289621f

commit eb2e0d02e494c55d5e3721fe8a70f2e4f289621f
Author: jlebel <jlebel@chromium.org>
Date: Tue Feb 07 10:36:27 2017

macOS: Setting focus to the first profile in profile switcher

When opening the profile switcher menu using the shortcut (ctrl-shift-m), the first
profile (other than the current one) in the list should be highlighted. This should
happens only when opening the menu with the keyboard (and not with the mouse).

BUG= 674343 

Review-Url: https://codereview.chromium.org/2638853003
Cr-Commit-Position: refs/heads/master@{#448586}

[modify] https://crrev.com/eb2e0d02e494c55d5e3721fe8a70f2e4f289621f/chrome/browser/ui/cocoa/profiles/profile_chooser_controller.h
[modify] https://crrev.com/eb2e0d02e494c55d5e3721fe8a70f2e4f289621f/chrome/browser/ui/cocoa/profiles/profile_chooser_controller.mm

Can you attach screenshots of what the menu looks like with and without focus?

Here is an example on Linux with the dotted line around my Google profile: https://screenshot.googleplex.com/sLKsrYt23H9

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/233d5951645e51d856784682bd5c1b32b2f60f81

commit 233d5951645e51d856784682bd5c1b32b2f60f81
Author: jlebel <jlebel@chromium.org>
Date: Thu Feb 23 10:55:37 2017

Linux/Windows: Setting focus to the first profile in profile switcher

When opening the profile switcher menu using the shortcut (ctrl-shift-m), the first
profile (other than the current one) in the list should be highlighted. This should
happens only when opening the menu with the keyboard (and not with the mouse).

For macOS: crrev.com/2638853003 and crrev.com/2682153002

BUG= 674343 

Review-Url: https://codereview.chromium.org/2687693002
Cr-Commit-Position: refs/heads/master@{#452449}

[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/printing/print_dialog_cloud.cc
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/signin/chrome_signin_helper.cc
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/signin/signin_global_error.cc
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/ui/browser_commands.cc
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/ui/browser_window.h
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/ui/chrome_pages.cc
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/ui/cocoa/browser_window_cocoa.h
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/ui/cocoa/browser_window_cocoa.mm
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/ui/passwords/manage_passwords_ui_controller.cc
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/ui/views/frame/avatar_button_manager.cc
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/ui/views/frame/browser_view.cc
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/ui/views/frame/browser_view.h
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/ui/views/profiles/profile_chooser_view.cc
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/ui/views/profiles/profile_chooser_view.h
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/ui/views/profiles/profile_chooser_view_browsertest.cc
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/ui/webui/history_login_handler.cc
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/ui/webui/options/sync_setup_handler.cc
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/ui/webui/settings/people_handler.cc
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/ui/webui/signin/inline_login_handler_impl.cc
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/browser/ui/webui/signin/login_ui_service.cc
[modify] https://crrev.com/233d5951645e51d856784682bd5c1b32b2f60f81/chrome/test/base/test_browser_window.h