[gtk+] (14 commits) Non-fast-forward update to branch wip/native-file-chooser

[Alexander Larsson <alexl src gnome org>]

The branch 'wip/native-file-chooser' 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:

  a6b4677... TreeModelFilter: Fix uninitialized memory read.
  db36986... Make GtkFileChooser interface require a GObject
  adc9a96... Add GtkNativeDialog abstract base class
  bedc197... GtkFileFilter: Add private function to represent filter as 
  f1f0bb2... GtkFileChooserNative: Fallback and win32 implementation
  4fbf06c... GtkFileChooserButton: Use native dialogs
  9bc8f78... testgtk: Add native dialog tests
  1bc352b... Mention native file choosers in NEWS
  eb96864... docs: Move GtkNativeDialog section to "abstract base classe
  ca2042e... gtk3-demo: Add open file to the application demo

Commits added to the branch:

  f327ef3... scrolledwindow: Use permanent CSS nodes (*)
  de3ad37... placessidebar: Use an element name (*)
  35eaca2... Adwaita: Update places sidebar styling (*)
  199e35f... HighContrast: Update places sidebar styling (*)
  1c46a02... TreeModelFilter: Fix uninitialized memory read.
  0f6c768... Make GtkFileChooser interface require a GObject
  81cef00... Add GtkNativeDialog abstract base class
  693db08... GtkFileFilter: Add private function to represent filter as 
  6a286f9... GtkFileChooserNative: Fallback and win32 implementation
  b3b68ea... GtkFileChooserButton: Use native dialogs
  c93b94f... testgtk: Add native dialog tests
  bb931f2... Mention native file choosers in NEWS
  7bfa0bb... docs: Move GtkNativeDialog section to "abstract base classe
  3bf5291... gtk3-demo: Add open file to the application demo

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