[gtk+/wip/ebassi/gsk-renderer] (19 commits) ...gsk: Reuse VAOs with identical buffers

[Emmanuele Bassi <ebassi src gnome org>]

Summary of changes:

  63ea361... Drop an unused variable (*)
  07823e2... Some debug help (*)
  8bac2f7... Add details to css render nodes (*)
  b0315e7... Allow selective debug spew (*)
  a4c335f... button: Restore focus (*)
  5196c3b... gadget: Add a has_content vfunc (*)
  a66166c... GtkExpander: Convert to indirect rendering (*)
  602b13a... Prevent box gadget content from being drawn twice (*)
  8cccdd8... GtkCheckButton: Convert to indirect rendering (*)
  66c2482... gadget: Fix handling of custom content (*)
  8e2161a... GtkListBox: Convert to indirect rendering (*)
  5648989... gsk: Build docs (*)
  c4ea9e2... Small fixes for the docs (*)
  1c79407... Small documentation additions (*)
  3875145... GtkButtonBox: Convert to indirect rendering (*)
  a89494c... Convert GtkComboBox to indirect rendering (*)
  3c312a4... Covert GtkOverlay to indirect rendering (*)
  4875819... gsk: Remove child-transform from render nodes
  34858c2... gsk: Reuse VAOs with identical buffers

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