power: Turn backlight on when external display is unplugged.
This ensures that the internal backlight is on after an
external display is disconnected. It also moves the
handling of other cases where the backlight should be forced
on, such as session state change or power button being
pressed, into InternalBacklightController.
BUG=chromium:218387
TEST=added unit tests
Change-Id: I71a3ebc9c82e04c64bcc74655d5a0b4e95efd2a2
Reviewed-on: https://gerrit.chromium.org/gerrit/46817
Tested-by: Daniel Erat <derat@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Commit-Queue: Daniel Erat <derat@chromium.org>
13 files changed
