[simple-scan] snap: Update yaml to use gnome extension

[Robert Ancell <rancell src gnome org>]

commit 7760db46b4d4ddba0597adbf21e78a39bd9955d9
Author: Heather Ellsworth <hellsworth gnome org>
Date:   Thu Oct 3 08:49:40 2019 +0000

    snap: Update yaml to use gnome extension

 snap/snapcraft.yaml | 37 ++-----------------------------------
 1 file changed, 2 insertions(+), 35 deletions(-)
---
diff --git a/snap/snapcraft.yaml b/snap/snapcraft.yaml
index 3697500..d9c071b 100644
--- a/snap/snapcraft.yaml
+++ b/snap/snapcraft.yaml
@@ -8,24 +8,6 @@ grade: stable # must be 'stable' to release into candidate/stable channels
 confinement: strict
 base: core18
 
-plugs:
-  gnome-3-28-1804:
-    interface: content
-    target: $SNAP/gnome-platform
-    default-provider: gnome-3-28-1804
-  gtk-3-themes:
-    interface: content
-    target: $SNAP/data-dir/themes
-    default-provider: gtk-common-themes
-  icon-themes:
-    interface: content
-    target: $SNAP/data-dir/icons
-    default-provider: gtk-common-themes
-  sound-themes:
-    interface: content
-    target: $SNAP/data-dir/sounds
-    default-provider: gtk-common-themes
-
 slots:
   # for GtkApplication registration
   simple-scan:
@@ -36,8 +18,6 @@ slots:
 apps:
   simple-scan:
     plugs:
-      - desktop
-      - desktop-legacy
       - network
       - network-control
       - home
@@ -47,27 +27,14 @@ apps:
       - system-observe
       - io-ports-control
       - raw-usb
-      - unity7
-    command: bin/desktop-launch ${SNAP}/usr/bin/simple-scan
+    command: usr/bin/simple-scan
+    extensions: [gnome-3-28]
     desktop: usr/share/applications/simple-scan.desktop
     environment:
       GSETTINGS_SCHEMA_DIR: $SNAP/share/glib-2.0/schemas
 
 parts:
-  desktop-gnome-platform:
-    source: https://github.com/ubuntu/snapcraft-desktop-helpers.git
-    source-subdir: gtk
-    plugin: make
-    make-parameters: ["FLAVOR=gtk3"]
-    build-packages:
-      - build-essential
-      - libgtk-3-dev
-    override-build: |
-      snapcraftctl build
-      mkdir -pv $SNAPCRAFT_PART_INSTALL/gnome-platform
-
   libsane:
-    after: [desktop-gnome-platform]
     source: https://salsa.debian.org/debian/sane-backends.git
     source-type: git
     source-tag: upstream/1.0.27