[mutter] (5 commits) Non-fast-forward update to branch wip/carlosg/wacom-x11-mode-switch

[Carlos Garnacho <carlosg src gnome org>]

The branch 'wip/carlosg/wacom-x11-mode-switch' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  6aba87a... x11: Check wacom button flags to determine whether button i

Commits added to the branch:

  1c89fce... stack: Allow promoting transient windows to their parent's  (*)
  599d8e3... stack: Move HAS_TRANSIENT_TYPE macro to window-private (*)
  b753213... window: Add get_default_layer() helper (*)
  c843102... stack: Delegate layer calculation to a window vfunc (*)
  6f4c7d6... x11: Check wacom button flags to determine whether button i

(*) This commit already existed in another branch; no separate mail sent