[mutter] (6 commits) Non-fast-forward update to branch wip/carlosg/clip-regions

[Carlos Garnacho <carlosg src gnome org>]

The branch 'wip/carlosg/clip-regions' 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:

  be778fd... compositor: Use redraw clip region to cull out children
  9dc9356... cogl: Add support for clipping regions
  1e41df3... clutter/cogl: Use regions for clipping if necessary
  62c8caf... cogl: Drop unused struct field
  825524e... clutter: Check updated devices with the current clip
  4988983... clutter: Drop unused API

Commits added to the branch:

  96baf66... cogl: Add support for clipping regions
  ed9a292... clutter/cogl: Use regions for clipping if necessary
  04a4ad4... compositor: Use redraw clip region to cull out children
  e68ae44... cogl: Drop unused struct field
  066304d... clutter: Check updated devices with the current clip
  c763722... clutter: Drop unused API