[sushi] Remove custom GTK theming bits

[Cosimo Cecchi <cosimoc src gnome org>]

commit 269d63d4fa15792e182c8f27564761aa4b2d4f0b
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Wed Jun 19 13:21:03 2019 -0700

    Remove custom GTK theming bits
    
    Many of these just don't work anymore, but in general we are fine
    with the default Adwaita dark theme.

 src/meson.build                                    |  8 ---
 src/org.gnome.NautilusPreviewer.data.gresource.xml |  6 --
 src/resources/gtk-style.css                        | 67 ----------------------
 src/ui/application.js                              |  6 --
 4 files changed, 87 deletions(-)
---
diff --git a/src/meson.build b/src/meson.build
index 193f009..18faf73 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -3,14 +3,6 @@ gnome = import('gnome')
 # Compile libsushi and its introspection data
 subdir('libsushi')
 
-sushi_data_resources = gnome.compile_resources(
-    'org.gnome.NautilusPreviewer.data',
-    'org.gnome.NautilusPreviewer.data.gresource.xml',
-    gresource_bundle: true,
-    install: true,
-    install_dir: pkgdatadir,
-)
-
 sushi_src_resources = gnome.compile_resources(
     'org.gnome.NautilusPreviewer.src',
     'org.gnome.NautilusPreviewer.src.gresource.xml',
diff --git a/src/ui/application.js b/src/ui/application.js
index 6348be9..896d493 100644
--- a/src/ui/application.js
+++ b/src/ui/application.js
@@ -69,12 +69,6 @@ var Application = GObject.registerClass(class Application extends Gtk.Applicatio
     }
 
     _defineStyleAndThemes() {
-        let provider = new Gtk.CssProvider();
-        provider.load_from_resource('/org/gnome/NautilusPreviewer/gtk-style.css');
-        Gtk.StyleContext.add_provider_for_screen(Gdk.Screen.get_default(),
-                                                 provider,
-                                                 600);
-
         let settings = Gtk.Settings.get_default();
         settings.gtk_application_prefer_dark_theme = true;
     }