quickSettings: Add background apps menu

Sandboxed apps that run without a window are detected by the new
background monitoring service, introduced by xdg-desktop-portal.

We have an opportunity to improve the predictability of the desktop
and ensure that application state in transparently reported to users
by showing these apps, and allowing them to closed.

Add a new background apps menu to the quick settings, that is always
added at the bottom of the popover, and has a slightly custom, flat
style applied to it.

Show background-running apps in this menu, and allow closing them
by first attempting to execute the 'quit' action through D-Bus, and
if that fails, sending SIGKILL to the process.

See https://gitlab.gnome.org/Teams/Design/os-mockups/-/issues/191

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2624>

1 files changed, 24 insertions, 0 deletions

diff --git a/widgets/_quick-settings.scss b/widgets/_quick-settings.scss
index 0064aee..6a4c42d 100644
--- a/widgets/_quick-settings.scss
+++ b/widgets/_quick-settings.scss
@@ -149,3 +149,27 @@
 }
 
 .device-subtitle { color: transparentize($fg_color, 0.5); }
+
+// background apps
+
+.background-apps-quick-toggle {
+  min-height: 40px;
+  background-color: transparent;
+
+  & StIcon { icon-size: $base_icon_size !important; }
+}
+
+.background-app-item {
+  & .title { @extend %heading; }
+  & .subtitle { @extend %caption; }
+  & .popup-menu-icon {
+    icon-size: $large_icon_size !important;
+    -st-icon-style: regular !important;
+  }
+  & .close-button {
+    @extend .icon-button;
+    padding: $base_padding;
+  }
+
+  &.popup-inactive-menu-item { color: $fg_color; }
+}