chromeos: Make touchscreen global state default to enabled.

Update ash::TouchDevicesController's
global_touchscreen_enabled_ member to default to true rather
than false. In practice, it's usually initialized just after
startup based on powerd's initial backlights-forced-off
state, but it feels safer to leave the touchscreen enabled
by default if initialization fails for some reason.

Bug: 778156
Change-Id: I8518783b2d2366ca3a48d42023d862bb0e073530
Reviewed-on: https://chromium-review.googlesource.com/739959
Reviewed-by: Qiang(Joe) Xu <[email protected]>
Commit-Queue: Dan Erat <[email protected]>
Cr-Commit-Position: refs/heads/master@{#511921}
2 files changed