[mutter] clutter/input-device: Replace device check with assertion

[Carlos Garnacho <carlosg src gnome org>]

commit 786305f7d687c4523504f98b2e60c8d90c1e7920
Author: Jonas Dreßler <verdre v0yd nl>
Date:   Mon Feb 4 22:22:48 2019 +0100

    clutter/input-device: Replace device check with assertion
    
    We only call _clutter_input_device_update with devices that are not
    Keyboard devices. Also passing a Keyboard device to a function whose
    primary purpose is picking should be considered a bug in the caller.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/547

 clutter/clutter/clutter-input-device.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/clutter/clutter/clutter-input-device.c b/clutter/clutter/clutter-input-device.c
index 1375e5a4d..be01062cc 100644
--- a/clutter/clutter/clutter-input-device.c
+++ b/clutter/clutter/clutter-input-device.c
@@ -1036,9 +1036,10 @@ _clutter_input_device_update (ClutterInputDevice   *device,
   ClutterActor *new_cursor_actor;
   ClutterActor *old_cursor_actor;
   ClutterPoint point = { -1, -1 };
+  ClutterInputDeviceType device_type = device->device_type;
 
-  if (device->device_type == CLUTTER_KEYBOARD_DEVICE)
-    return NULL;
+  g_assert (device_type != CLUTTER_KEYBOARD_DEVICE &&
+            device_type != CLUTTER_PAD_DEVICE);
 
   stage = device->stage;
   if (G_UNLIKELY (stage == NULL))