Pass allow_off parameter to DecreaseScreenBrightness dbus method

Modify the dbus_method_call1 to allow specifying the type of the
parameter.  Used to be able to pass int to the user_activity
method and bool to the DecreaseScreenBrightness method.   The
DecreaseScreenBrightness parameter allow_off is always set to
false, as it doesn't make much sense to allow the screen to go
completely off while frecon is active.

BUG=chromium:441558
TEST=test brightness up/down on link while frecon is active

Change-Id: Iced5e36ff819643f5f4f74d1199a1d996aee0a03
Previous-Reviewed-on: https://chromium-review.googlesource.com/258151
Trybot-Ready: David Sodman <dsodman@chromium.org>
(cherry picked from commit 19e4f9d8a481edbe9f711a4988328b0ec95c56a9)
Reviewed-on: https://chromium-review.googlesource.com/259111
Tested-by: David Sodman <dsodman@chromium.org>
Reviewed-by: David Sodman <dsodman@chromium.org>
3 files changed