Close popups in the correct order

According to the protocol, child popups have to be closed before
parents, but QMenuBar/QMenu will sometimes close the parent first.

Change-Id: Id027ac483b727a19388df619fe1503d794e12c12
Task-number: QTBUG-62048
Reviewed-by: Johan Helsing <johan.helsing@qt.io>

src/plugins/platforms/wayland/qwaylandwindow.cpp

@@ -341,9 +341,26 @@ void QWaylandWindow::sendExposeEvent(const QRect &rect)
         QWindowSystemInterface::handleExposeEvent(window(), rect);
 }
 
+
+static QVector<QPointer<QWaylandWindow>> activePopups;
+
+void QWaylandWindow::closePopups(QWaylandWindow *parent)
+{
+    while (!activePopups.isEmpty()) {
+        auto popup = activePopups.takeLast();
+        if (popup.isNull())
+            continue;
+        if (popup.data() == parent)
+            return;
+        popup->reset();
+    }
+}
+
 void QWaylandWindow::setVisible(bool visible)
 {
     if (visible) {
+        if (window()->type() == Qt::Popup)
+            activePopups << this;
         initWindow();
         mDisplay->flushRequests();
 
@@ -357,6 +374,8 @@ void QWaylandWindow::setVisible(bool visible)
         // case 'this' will be deleted. When that happens, we must abort right away.
         QPointer<QWaylandWindow> deleteGuard(this);
         QWindowSystemInterface::flushWindowSystemEvents();
+        if (!deleteGuard.isNull() && window()->type() == Qt::Popup)
+            closePopups(this);
         if (!deleteGuard.isNull())
             reset();
     }

src/plugins/platforms/wayland/qwaylandwindow_p.h

@@ -253,6 +253,7 @@ private:
     bool shouldCreateSubSurface() const;
     void reset();
     void sendExposeEvent(const QRect &rect);
+    static void closePopups(QWaylandWindow *parent);
 
     void handleMouseEventWithDecoration(QWaylandInputDevice *inputDevice, const QWaylandPointerEvent &e);