GitLab

changes:
* Move kTapToClickEnabled and kOwnerTapToClickEnabled handling to ash
* In this CL, above pref registrations are still in chrome side because
  ash side doesn't have device owner info yet.

TBR=stevenjb@chromium.org

Bug: 817643
Test: manual and test coverage
Change-Id: I6b11eb65a40968eada67ebf2e8b4fb3f1f0eaddc
Reviewed-on: https://chromium-review.googlesource.com/1116210
Commit-Queue: Qiang Xu <warx@google.com>
Reviewed-by: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570842}