[ozone/wayland] Fix crash with html drop-down menus.

html drop-down menus are represented by XDG popup windows, which don't
have a parent window associated in aura. Thus, null accelerated widget is passed,
which can't be used to find a parent. Instead, a currently focused window
must be used.

Actually, it is so in the WaylandWindow::GetParentWindow, but
there is a redundant check, which doesn't call the GetParentWindow if the
parent widget is null.

Fix: remove the if check and always call the GetParentWindow.

TBR=rjkroege@chromium.org

Bug: 578890
Change-Id: I0ecab40d80929fd4ca4445cbb3ae753e00b3d458
Reviewed-on: https://chromium-review.googlesource.com/1149363
Reviewed-by: Maksim Sisov <msisov@igalia.com>
Reviewed-by: Robert Kroeger <rjkroege@chromium.org>
Commit-Queue: Maksim Sisov <msisov@igalia.com>
Cr-Commit-Position: refs/heads/master@{#578249}
2 files changed