Support XDG activation

QWaylandLayerShellIntegration has virtual hooks for Xdg Activation.

This is important to hook up in layer shell because activation using
requestActivate in Qt will go through this path. It also means we have
support for us to drop the implementation in KWindowSystem in favour of
calling into Qt.

src/qwaylandxdgactivationv1_p.h

@@ -0,0 +1,48 @@
+/** Copyright (C) 2020 Aleix Pol Gonzalez <aleixpol@kde.org>
+ *  SPDX-License-Identifier: LGPL-3.0-or-later
+ */
+
+#ifndef QWAYLANDXDGACTIVATIONV1_P_H
+#define QWAYLANDXDGACTIVATIONV1_P_H
+
+#include "qwayland-xdg-activation-v1.h"
+#include <QObject>
+
+#include <QtWaylandClient/QWaylandClientExtension>
+
+namespace QtWaylandClient
+{
+class QWaylandDisplay;
+class QWaylandSurface;
+}
+
+class QWaylandXdgActivationTokenV1 : public QObject, public QtWayland::xdg_activation_token_v1
+{
+    Q_OBJECT
+public:
+    ~QWaylandXdgActivationTokenV1() override
+    {
+        destroy();
+    }
+
+protected:
+    void xdg_activation_token_v1_done(const QString &token) override
+    {
+        Q_EMIT done(token);
+    }
+
+Q_SIGNALS:
+    void done(const QString &token);
+};
+
+class QWaylandXdgActivationV1 : public QWaylandClientExtensionTemplate<QWaylandXdgActivationV1>, public QtWayland::xdg_activation_v1
+{
+public:
+    QWaylandXdgActivationV1();
+    ~QWaylandXdgActivationV1() override;
+
+    QWaylandXdgActivationTokenV1 *
+    requestXdgActivationToken(QtWaylandClient::QWaylandDisplay *display, struct ::wl_surface *surface, std::optional<uint32_t> serial, const QString &app_id);
+};
+
+#endif // QWAYLANDXDGACTIVATIONV1_P_H