sky, didn't you have to do something recently for touchpad (not screen) enable/disable?

I haven't started yet. I added Set{Get}TouchscreenEnabled in ShellDelegate. So I would to like to help here. But let me know if you have started. Thanks!

Indeed. The right thing to do is update InputDeviceControllerClient with the logic you need (it has the setter, but not toggle or get). InputDeviceControllerClient is intended for the functionality you want. I've updated the summary to reflect this.

cool, thanks! I can start working on this.

Hi Scott, I think these three methods should move to ash/. They touch the prefs which we can move from chrome/ to ash/. And from ash/ we can call InputDeviceControllerClient's SetInternalTouchpadEnabled and SetTouchscreensEnabled methods.

SGTM

 Issue 764486  has been merged into this issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f1400a36711fe2f8d473a13121fb7498dec412b0

commit f1400a36711fe2f8d473a13121fb7498dec412b0
Author: Qiang Xu <warx@chromium.org>
Date: Thu Sep 14 02:28:30 2017

mash: remove ToggleTouchpad, Get{Set}TouchscreenEnabled from
ShellDelegate

Changes:
- Create ash::TouchDevicesController to host the removed methods from
ShellDelegate and they talk to ui::InputDeviceControllerClient.
- Move kTouchpadEnabled and kTouchscreenEnabled prefs from chrome to ash.
- Add test coverage for user profile kTouchpadEnabled and
kTouchscreenEnabled. They are triggered by debug accelerator. The
touchscreen global enabled source is already tested in
TabletPowerButtonControllerTest.

Bug:  763253 ,  764486 
Test: device test and added test coverage.
Change-Id: Ic2149132fea3107f2eac217163b166545da5d1c9
Reviewed-on: https://chromium-review.googlesource.com/662657
Commit-Queue: Qiang(Joe) Xu <warx@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#501846}
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/BUILD.gn
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/accelerators/debug_commands.cc
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/accessibility/accessibility_controller.cc
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/accessibility/accessibility_controller.h
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/mus/shell_delegate_mus.cc
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/mus/shell_delegate_mus.h
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/public/cpp/BUILD.gn
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/public/cpp/ash_pref_names.cc
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/public/cpp/ash_pref_names.h
[delete] https://crrev.com/b9df3441dc4c014462b6d0a29d2ade02abdc9a83/ash/public/cpp/touchscreen_enabled_source.h
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/session/session_controller.cc
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/session/session_controller.h
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/shell.cc
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/shell.h
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/shell/shell_delegate_impl.cc
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/shell/shell_delegate_impl.h
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/shell_delegate.h
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/system/power/power_button_display_controller.cc
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/system/power/tablet_power_button_controller_unittest.cc
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/test_shell_delegate.cc
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/test_shell_delegate.h
[add] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/touch/touch_devices_controller.cc
[add] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/touch/touch_devices_controller.h
[add] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/ash/touch/touch_devices_controller_unittest.cc
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/chrome/browser/chromeos/preferences.cc
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/chrome/browser/chromeos/system/input_device_settings.cc
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/chrome/browser/chromeos/system/input_device_settings.h
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/chrome/browser/prefs/browser_prefs.cc
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/chrome/browser/ui/ash/chrome_shell_delegate.cc
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/chrome/browser/ui/ash/chrome_shell_delegate.h
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/chrome/common/pref_names.cc
[modify] https://crrev.com/f1400a36711fe2f8d473a13121fb7498dec412b0/chrome/common/pref_names.h