[gtk] (12 commits) ...Merge branch 'misc-speedups' into 'master'

[Matthias Clasen <matthiasc src gnome org>]

Summary of changes:

  466d33c... ngl: Speed up clipping calculations a bit (*)
  f88efb8... ngl: Reduce type checking overhead (*)
  7fb1389... gsk: Add a private getter for container children (*)
  b695ef9... gsk: Add a shortcut for a common transform case (*)
  0ef1219... gsk: Optimize gsk_transform_to... (*)
  ae3e586... gridlayout: Avoid some unnecessary overhead (*)
  98986a2... layoutmanager: Avoid some overhead (*)
  7044951... widget: Avoid GObject data for action muxer (*)
  ee6491f... widget: Avoid some unnecessary back-and-forth casting (*)
  0d8dd0c... sizerequest: Keep branches in sync (*)
  d764603... sizerequest: Simplify some code (*)
  4dc4c00... Merge branch 'misc-speedups' into 'master'

(*) This commit already existed in another branch; no separate mail sent