[gtk] (40 commits) ...Merge branch 'icon-theme-rework' into 'master'

[Alexander Larsson <alexl src gnome org>]

Summary of changes:

  aef67bd... GtkIconTheme: Make the base GtkIconTheme threadsafe
  3ac7e30... icon theme: Make GtkIconInfo cached data threadsafe
  b96ab74... GtkIconInfo: Implement paintable
  aefd844... GtkIconHelper use GtkIconInfo as paintable
  c42977a... Convert trivial users of icon theme loading to use info as 
  53c5427... Add gtk_icon_info_snapshot_with_colors() and use instead of
  884e06a... icon theme: Add gtk_icon_info_download_texture() function
  dbe0212... icons: Convert use of load() to download_texture()
  afa6cc2... Break out cairo color matrix recoloring to gdk_cairo_image_
  6ffb54f... icon-theme: Add gtk_icon_info_download_colored_texture()
  97b24b0... tests: Use gtk_icon_info_download_colored_texture instead o
  71b3b54... icon-theme: Add async icon loader
  317b395... icon-theme: Drop loading_themes recursion check
  0d666f0... icon-theme: Use gtk_icon_theme_choose_icon_async in tests
  6af4b6a... icon-theme: Drop all load() calls from GtkIconInfo
  6a15e91... Rename GtkIcon widget to GtkBuiltinIcon
  e2f7786... icon-theme: Rename GtkIconInfo to GtkIcon
  b087f9c... icon-theme: Drop the _for_scale() versions and always take 
  1e6a825... icon-theme: Clean up locking
  56ec748... icon theme: Actually don't block in gtk_icon_theme_choose_i
  1be9322... icon theme: Actually use scale in choose_icon_async()
  55db9d0... icon-theme: Only add theme load profiler mark if we actuall
  d2f26b2... icon-theme: Improve profiler mark for icon loads
  ff3e022... icon helper: Remove profiler mark
  6a8001f... icon-theme: Preload default icon themes in thread
  d1c6d78... GtkImage: Preload icons during css validation
  2b20212... icon-theme: Fix indentation of matrix values
  b227a2f... icon-theme: Use GtkSnapshot, not GdkSnapshot
  ff0642b... icon-theme: Remove trailing whitespaces
  f7cd2a7... Fix warnings in gdk gir build
  2ec51b7... icon-theme: Update the docs
  27799ba... Remove final references to "icon info" with just "icon"
  5f8c2b5... indentation: fix various alignment issues
  d1cd578... icon-theme: Add i/o priority to choose_icon_async()
  c69327c... icon-theme: Show which icon loads are threaded in profile m
  498ab6a... IconHelper: Only preload icons once
  b67d582... GtkIconHelper: Preload icons for mapped widgets with higher
  d478ae1... icon-theme: Avoid reentrancy issues while loading icon them
  09ef67a... icon-theme: Add icon theme name in profiler mark
  99c89d6... Merge branch 'icon-theme-rework' into 'master'