Add GNOME-like client-side decoration plugin

Adds a client-side decoration plugin implementing GNOME's Adwaita style.
This is trying to follow GTK4 Adwaita style, using xdg-desktop-portal to
get user's configuration in order to get whether a light or dark colors
should be used and to get the titlebar button layout. This plugin is now
used on GNOME by default, while defaulting to the original behavior for
non-GNOME DEs. It depends on QtSvg used to draw titlebar buttons so in
case QtSvg is not found, this plugin will not be build.

[ChangeLog][QtWaylandClient][Added GNOME-like client-side decoration
plugin]

Fixes: QTBUG-120070
Change-Id: I0f1777c4e0aa3467dafbbae8004b594cc82f9aa0
Reviewed-by: David Edmundson <davidedmundson@kde.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/src/plugins/decorations/adwaita/CMakeLists.txt b/src/plugins/decorations/adwaita/CMakeLists.txt
new file mode 100644
index 000000000..b318c2b8b
--- /dev/null
+++ b/src/plugins/decorations/adwaita/CMakeLists.txt
@@ -0,0 +1,25 @@
+# Copyright (C) 2023 The Qt Company Ltd.
+# SPDX-License-Identifier: BSD-3-Clause
+
+#####################################################################
+## QWaylandAdwaitaDecorationPlugin Plugin:
+#####################################################################
+
+qt_internal_add_plugin(QWaylandAdwaitaDecorationPlugin
+    OUTPUT_NAME adwaita
+    PLUGIN_TYPE wayland-decoration-client
+    SOURCES
+        main.cpp
+        qwaylandadwaitadecoration.cpp
+    LIBRARIES
+        Qt::Core
+        Qt::DBus
+        Qt::Gui
+        Qt::Svg
+        Qt::WaylandClientPrivate
+        Wayland::Client
+)
+
+#### Keys ignored in scope 1:.:.:bradient.pro:<TRUE>:
+# OTHER_FILES = "bradient.json"
+