power: Add optional udev rules to disable touchpad wakeup.

Add a 92-powerd-tags-no-touchpad-wakeup.rules file that can
be installed to instruct powerd to unconditionally disable
touchpad wakeup.

BUG=chromium:710472
TEST=none

Change-Id: I45314138ceb9532cf50794e768ff30b53293ee02
Reviewed-on: https://chromium-review.googlesource.com/477592
Commit-Ready: Dan Erat <derat@chromium.org>
Tested-by: Dan Erat <derat@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
(cherry picked from commit 452cdd05a9f1065681ea4cd0090f417a44784310)
Reviewed-on: https://chromium-review.googlesource.com/481903
Reviewed-by: Dan Erat <derat@chromium.org>
diff --git a/power_manager/udev/optional/92-powerd-tags-no-touchpad-wakeup.rules b/power_manager/udev/optional/92-powerd-tags-no-touchpad-wakeup.rules
new file mode 100644
index 0000000..093643b
--- /dev/null
+++ b/power_manager/udev/optional/92-powerd-tags-no-touchpad-wakeup.rules
@@ -0,0 +1,2 @@
+# Don't let the touchpad wake the device from sleep.
+ENV{POWERD_ROLE}=="internal_touchpad", KERNEL=="input*", ENV{POWERD_TAGS_WAKEUP}="wakeup wakeup_disabled"