[gtk/matthiasc/for-master] (29 commits) ...css: Don't lose inset when computing shadows

[Matthias Clasen <matthiasc src gnome org>]

Summary of changes:

  7da6fdc... widget: Stop using style context internally (*)
  731ae8f... gskpango: Stop using style context getters (*)
  f1ff699... drag icon: Stop using style context getters (*)
  ac902e6... popover: Stop using style context getters (*)
  0623b00... Merge branch 'style-context-redux' into 'master' (*)
  64e026d... Revert "Ensure icon themes are loaded with other themes" (*)
  03595f9... Fix a scrollbar sizing issue (*)
  3d9e339... lookup stats (*)
  d8144ec... Adwaita: drop the * (*)
  53c22bf... Adwaita: take out an unnecessary rule (*)
  0df0de0... css: Split style into groups (*)
  b4e2df8... Revert "css: Split style into groups" (*)
  7bebc3e... Revert "lookup stats" (*)
  4287f0d... window: Replace GtkStyleContext use to get surface transfor (*)
  1a56a10... cssimage: Add gtk_css_image_to_string() (*)
  f62535a... gl renderer: Avoid some work when rendering border nodes (*)
  69fe705... GtkCssImageUrl: Implement is_computed() (*)
  36e3f4d... cssprovider: Parse selectors without a GList (*)
  355a417... cssparser: make a few local variables const (*)
  7ccd659... Remove gtkutils{.c,private.h} (*)
  942a932... render: Remove gtk_render_background_get_clip (*)
  77e0d36... Add pure and const annotations to various functions (*)
  2e25698... renderbackground: Avoid unnecessary work in snapshot_backgr (*)
  30b37dd... widget: Restructure pick() a bit (*)
  352c9ba... dimensionvalue: Add gtk_css_{dimension,corner}_value_is_zer (*)
  c7ea83c... cssboxes: Try to avoid doing work for rectangular boxes (*)
  a16e1cb... cssdimensionvalue: Remove an outdated comment (*)
  05b9a99... gsk: Remove some unused defines (*)
  3cdde3f... css: Don't lose inset when computing shadows

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