[gtk] (9 commits) Non-fast-forward update to branch fix-icontheme-invalidation

[Matthias Clasen <matthiasc src gnome org>]

The branch 'fix-icontheme-invalidation' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  a16dded... css: Compare icon theme serials
  7d0b2ae... widget: Add a system_setting_changed vfunc
  6001af0... window: Use gtk_system_setting_change
  21196b0... settings: Call gtk_system_setting_changed
  36cf55e... settings: invalidate styles when animations change
  e72319e... icontheme: Call gtk_system_setting_changed
  9efcd3f... image: Invalidate icon helper when icon theme changes
  e45cd87... widget: Update when font settings change
  5d327ae... Drop gtk_style_context_reset_widgets
  201fc4a... Drop gtk_widget_reset_style

Commits added to the branch:

  58ca3b0... css: Compare icon theme serials
  723d57e... widget: Add a system_setting_changed vfunc
  129b8bb... window: Use gtk_system_setting_change
  4b13d99... settings: Call gtk_system_setting_changed
  a59cb5d... icontheme: Call gtk_system_setting_changed
  679863a... image: Invalidate icon helper when icon theme changes
  7b4378b... widget: Update when font settings change
  a199060... Drop gtk_style_context_reset_widgets
  94906d0... Drop gtk_widget_reset_style