Bug 1864382 [Linux] Use gdk_window_get_root_origin() to get origin for popup windows too and apply workaround for Gtk3 < 3.24.35 r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D193497

widget/gtk/nsWindow.cpp

@@ -3187,20 +3187,20 @@ void nsWindow::SetFocus(Raise aRaise, mozilla::dom::CallerType aCallerType) {
 
 LayoutDeviceIntRect nsWindow::GetScreenBounds() {
   const LayoutDeviceIntPoint origin = [&] {
-    // XXX Can't we use mGdkWindow here?
-    //
-    // Use the point including window decorations. Don't do this for popups,
-    // because we get wrong coordinates for gtk for override-redirect windows in
-    // HiDPI screens, and those don't have window decorations anyways.
-    //
-    // See https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/4820
-    if (mContainer && mWindowType != WindowType::Popup) {
-      gint x, y;
-      gdk_window_get_root_origin(gtk_widget_get_window(GTK_WIDGET(mContainer)),
-                                 &x, &y);
-      return GdkPointToDevicePixels({x, y});
+    if (mIsDestroyed || !mGdkWindow) {
+      return LayoutDeviceIntPoint(0, 0);
     }
-    return WidgetToScreenOffset();
+    gint x, y;
+    gdk_window_get_root_origin(mGdkWindow, &x, &y);
+
+    // Workaround for https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/4820
+    // Bug 1775017 Gtk < 3.24.35 returns scaled values for
+    // override redirected window on X11.
+    if (gtk_check_version(3, 24, 35) != nullptr && GdkIsX11Display() &&
+        gdk_window_get_window_type(mGdkWindow) == GDK_WINDOW_TEMP) {
+      return LayoutDeviceIntPoint(x, y);
+    }
+    return GdkPointToDevicePixels({x, y});
   }();
 
   // mBounds.Size() is the window bounds, not the window-manager frame