[gtk] (42 commits) ...inspector: Add an fps overlay

[Benjamin Otte <otte src gnome org>]

Summary of changes:

  271820b... rendernode: Add gsk_render_node_diff() (*)
  29111a1... widget: Cache the render node (*)
  2d10c25... gtk: Add GtkWidgetPaintable (*)
  c0db409... magnifier: Redo with GtkWidgetPaintable (*)
  a6079b9... gsk: Implement gsk_render_node_diff() (*)
  b19d763... widget: Reorder gtk_widget_render() (*)
  d0873c7... gsk: Fold gsk_renderer_begin_draw_frame() into renderer (*)
  7c313c7... gsk: move begin/end_frame vfuncs into the renderers (*)
  925cbea... renderer: Track the previous node (*)
  7e078cd... gtk: Remove debug updates (*)
  a468714... widget: Stop tracking invalidations (*)
  73650c6... gtk: Remove gtk_widget_queue_draw_region() (*)
  e3a7173... snapshot: Remove clip argument from gtk_snapshot_new() (*)
  0f184d3... vulkan: Always render clip extents (*)
  4b72ea3... diff: Introduce GskDiffSettings (*)
  144637b... build: Switch order of subdirectories (*)
  200bbe8... diff: Allow aborting a diff (*)
  278ab3c... snapshot: Track clip as a rect only (*)
  4bf9063... widget: Cache clip from creating render node (*)
  a36b0f8... widget: Don't clip widgets anymore when snapshotting (*)
  f1f27ce... broadway: Improve error message (*)
  fc6de13... widget: Don't keep track of clip anymore. (*)
  1692039... widget: Remove clip from size-allocate vfunc (*)
  139882b... demos: Add an image demo for widget paintables (*)
  12fedca... widgetpaintable: Protect against too many signals (*)
  ffc7b2b... snapshot: Allow passing the bounds of the created paintable (*)
  c74854f... paintable: Introduce gdk_paintable_new_empty() (*)
  f974b48... widgetpaintable: Implement get_current_image() (*)
  a595a4c... testlist3: Set the actual row as drag icon (*)
  c855476... testgtk: Take an actual snapshot of a widget (*)
  4a513b7... reftests: Port from gtk_widget_draw() to snapshots (*)
  c06a790... widget: Remove gtk_widget_draw() (*)
  56e018b... widget: Remove GtkWidget.draw vfunc (*)
  1aacb14... testgtk: Remove draw signal usage (*)
  7a4e76a... treeview: Remove invalidation tracking code (*)
  0ea8395... image: Actually report a request mode (*)
  6c55096... inspector: Change semantics of inspector render node notify (*)
  cbf26fb... widget: Add gtk_widget_compute_bounds() (*)
  de99061... inspector: Introduce so-called "overlays" (*)
  2699c15... widget: Remove draw signal (*)
  6de4c63... inspector: Bring back debug updates (*)
  a5cb6aa... inspector: Add an fps overlay (*)

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