cros: Connecting a touchpad device should enter clamshell mode.

Like a mouse device, a touchpad device should have the same effect on
the ui mode, i.e., connecting a touchpad device should exit tablet mode
and enter clamshell mode.

Bug: b/118515248
Change-Id: I8529a79015779e2e4d52c2a429b8e0ccf68db463
Reviewed-on: https://chromium-review.googlesource.com/c/1306235
Reviewed-by: kylechar <kylechar@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Xiaoqian Dai <xdai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603653}
7 files changed