[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:

  b7b0d6f... cogl: Add support for clipping regions
  a6d911d... clutter/cogl: Use regions for clipping if necessary
  3e37a5b... compositor: Use redraw clip region to cull out children
  8dbc1d8... cogl: Drop unused struct field
  81ef15f... clutter: Check updated devices with the current clip
  7469d87... clutter: Drop unused API

Commits added to the branch:

  dfc7777... cogl: Add support for clipping regions
  67e651d... clutter/cogl: Use regions for clipping if necessary
  cf7693a... compositor: Use redraw clip region to cull out children
  5c0b365... cogl: Drop unused struct field
  98f0782... clutter: Check updated devices with the current clip
  e9b2635... clutter: Drop unused API