The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0

commit 74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0
Author: Anastasia Helfinstein <anastasi@google.com>
Date: Thu Dec 06 18:35:12 2018

Prepare Switch Access event handler for mash.

Create a Switch Access event handler in ash/, and convert the current
handler in chrome/ to a delegate.

Bug:  905439 
Change-Id: I7cca3cf8883f1e1fd0bfa6f5c02797ce020b46b5
Reviewed-on: https://chromium-review.googlesource.com/c/1354037
Reviewed-by: James Cook <jamescook@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: David Tseng <dtseng@chromium.org>
Commit-Queue: Anastasia Helfinstein <anastasi@google.com>
Cr-Commit-Position: refs/heads/master@{#614423}
[modify] https://crrev.com/74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0/ash/BUILD.gn
[modify] https://crrev.com/74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0/ash/accessibility/accessibility_controller.cc
[modify] https://crrev.com/74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0/ash/accessibility/accessibility_controller.h
[modify] https://crrev.com/74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0/ash/events/OWNERS
[add] https://crrev.com/74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0/ash/events/switch_access_event_handler.cc
[add] https://crrev.com/74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0/ash/events/switch_access_event_handler.h
[add] https://crrev.com/74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0/ash/events/switch_access_event_handler_unittest.cc
[modify] https://crrev.com/74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0/ash/public/interfaces/accessibility_controller.mojom
[modify] https://crrev.com/74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0/chrome/browser/accessibility/accessibility_extension_api.cc
[modify] https://crrev.com/74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0/chrome/browser/chromeos/BUILD.gn
[modify] https://crrev.com/74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0/chrome/browser/chromeos/accessibility/accessibility_manager.cc
[modify] https://crrev.com/74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0/chrome/browser/chromeos/accessibility/accessibility_manager.h
[modify] https://crrev.com/74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0/chrome/browser/chromeos/accessibility/switch_access_browsertest.cc
[delete] https://crrev.com/165281bde1ac0911644f1bc947c9a1e4e37af0f7/chrome/browser/chromeos/accessibility/switch_access_event_handler.cc
[delete] https://crrev.com/165281bde1ac0911644f1bc947c9a1e4e37af0f7/chrome/browser/chromeos/accessibility/switch_access_event_handler.h
[add] https://crrev.com/74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0/chrome/browser/chromeos/accessibility/switch_access_event_handler_delegate.cc
[add] https://crrev.com/74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0/chrome/browser/chromeos/accessibility/switch_access_event_handler_delegate.h
[modify] https://crrev.com/74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0/chrome/browser/chromeos/preferences.cc
[modify] https://crrev.com/74fe33533bbf0873b3944bffe8c9ec0f4f3f5ce0/chrome/browser/ui/ash/accessibility/accessibility_controller_client_unittest.cc