[gnome-control-center] (11 commits) Non-fast-forward update to branch wip/jsparber/background

[Julian Sparber <jsparber src gnome org>]

The branch 'wip/jsparber/background' 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:

  a163882... background: refactor cc-background-store
  00f92d6... background: make cc_background_grid_item_set_ref static and
  2178ac1... background: change name cc_background_grid_item_get_ref
  8da29a8... background: less exposure of the the wallpaper store
  ff8a8be... background: change base obj of CcBackgroundGridItem
  600054f... background: CcBackgroundGridItem::new returns its own typ
  0b78eaf... background: cache tumbnail for wallpaper gallery for a redr
  809e1c0... background: changed variable names and small style changes
  9aebc85... background: cache slideshow-emblem icon
  325b053... background: show only top border for gallery view
  e6e9c27... background: adapt meson.build for file changes
  5d9a897... background: change description for open in File and open in
  5f9792c... background: fix crash of g-c-c by opening gnome-photos
  370b09e... background: use autoptr where possible
  d5dedd2... background: clean up files and code and remove build warnin

Commits added to the branch:

  080c571... background: refactor cc-background-store
  912531d... background: make cc_background_grid_item_set_ref static and
  9915b3b... background: cache tumbnail for wallpaper gallery for a redr
  bf54d57... background: changed variable names and small style changes
  b9f20fb... background: cache slideshow-emblem icon
  78c783a... background: show only top border for gallery view
  ede20ea... background: adapt meson.build for file changes
  d326949... background: change description for open in File and open in
  855f58f... background: fix crash of g-c-c by opening gnome-photos
  5023527... background: use autoptr where possible
  144a7ef... background: clean up files and code and remove build warnin