[mutter] (5 commits) Non-fast-forward update to branch wip/carlosg/clip-me-harder

[Carlos Garnacho <carlosg src gnome org>]

The branch 'wip/carlosg/clip-me-harder' 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:

  f3a2459... compositor: Optimize shadows entirely if clip region is emp
  2812a22... compositor: Check frame bounds region before use
  ed6fff6... compositor: Fix check to clip beneath the window
  49cea68... compositor: Cull out areas covered by opaque windows
  30c1cf3... compositor: Clip obscured background areas

Commits added to the branch:

  c98d57f... compositor: Optimize shadows entirely if clip region is emp
  a6f7c85... compositor: Check frame bounds region before use
  b37fbf8... compositor: Fix check to clip beneath the window
  b6410c4... compositor: Cull out areas covered by opaque windows
  53eca1c... compositor: Clip obscured background areas