[gtk] (11 commits) Non-fast-forward update to branch wip/baedert/single-node-window

[Timm Bäder <baedert src gnome org>]

The branch 'wip/baedert/single-node-window' 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:

  70c5af9... widget: Remove GtkWindow special case in create_render_node
  c5f75e3... widget: Make 1 if out of 2 ifs
  83062ee... window: Remove custom snapshot() implementation
  80b8a83... window: Don't care about shadow in size_allocate()
  55df248... window: Don't care about shadow in measure()
  e577335... window: Remove decoration node
  a301d18... main: Inline propagate_{down,up} in propagate_internal()
  65ebeaf... window: Fix titled -> tiled typo
  3ecb688... /o\

Commits added to the branch:

  18286d6... window: Create constraint solver on demand
  c446e48... widget: Remove GtkWindow special case in create_render_node
  1bf2d44... widget: Make 1 if out of 2 ifs
  1701bf5... window: Remove custom snapshot() implementation
  06dad8f... window: Don't care about shadow in size_allocate()
  229409f... window: Don't care about shadow in measure()
  a0e9629... window: Remove decoration node
  3afc2bc... main: Inline propagate_{down,up} in propagate_internal()
  9d9ce5c... window: Fix titled -> tiled typo
  1ee7cdf... /o\
  8cd4ce5... window: ref() window before removing from toplevel list