input: Provide microsecond timestamps in motion events

Provide timestamps with microsecond granularity if the backend can
provide it. Backends that can't should set it to 0.

Signed-off-by: Jonas Ådahl <jadahl@gmail.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>

libweston/compositor.h

@@ -248,6 +248,7 @@ enum weston_pointer_motion_mask {
 
 struct weston_pointer_motion_event {
 	uint32_t mask;
+	uint64_t time_usec;
 	double x;
 	double y;
 	double dx;

libweston/libinput-device.c

@@ -86,6 +86,8 @@ handle_pointer_motion(struct libinput_device *libinput_device,
 	struct evdev_device *device =
 		libinput_device_get_user_data(libinput_device);
 	struct weston_pointer_motion_event event = { 0 };
+	uint64_t time_usec =
+		libinput_event_pointer_get_time_usec(pointer_event);
 	double dx_unaccel, dy_unaccel;
 
 	dx_unaccel = libinput_event_pointer_get_dx_unaccelerated(pointer_event);
@@ -94,6 +96,7 @@ handle_pointer_motion(struct libinput_device *libinput_device,
 	event = (struct weston_pointer_motion_event) {
 		.mask = WESTON_POINTER_MOTION_REL |
 			WESTON_POINTER_MOTION_REL_UNACCEL,
+		.time_usec = time_usec,
 		.dx = libinput_event_pointer_get_dx(pointer_event),
 		.dy = libinput_event_pointer_get_dy(pointer_event),
 		.dx_unaccel = dx_unaccel,