[gtk+] (3 commits) Non-fast-forward update to branch wip/attente/gtk-3-mir-fixes

[William Hua <williamhua src gnome org>]

The branch 'wip/attente/gtk-3-mir-fixes' 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:

  f48ef4c... mir: migrate away from deprecated mir api
  3faafc0... mir: delete commented debug output
  d706f9a... mir: deprecate gdk_mir_window_get_mir_surface ()

Commits added to the branch:

  7510080... mir: migrate away from deprecated mir api
  a96b8df... mir: delete commented debug output
  0a3bc3e... mir: deprecate gdk_mir_window_get_mir_surface ()