[gtk] (11 commits) ...Merge branch 'ngl-less-shaders' into 'master'

[Matthias Clasen <matthiasc src gnome org>]

Summary of changes:

  29501f5... ngl: Fix up uniform enums (*)
  19e3a6a... ngl: Consistently use gsk_scaled_premultiply (*)
  233969e... ngl: Refactor gsk_ngl_render_job_visit_border_node (*)
  4aa570b... ngl: Drop gsk_ngl_render_job_set_color (*)
  3f60c39... ngl: Rewrite gsk_ngl_render_job_visit_text_node (*)
  c1f98d6... ngl: Improve the gradient shaders (*)
  8aac574... ngl: Improve the coloring shader (*)
  51074ca... ngl: Small shader improvements (*)
  ed3f001... ngl: Don't bother with uniform border nodes (*)
  28de2ee... ngl: Special-case css backgrounds (*)
  24ec2cc... Merge branch 'ngl-less-shaders' into 'master'

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