x11: Don't wait on a MapNotify on override-redirect windows.
Some window managers do not send MapNotify on override-redirect
windows. Enlightenment doesn't send one, XFCE does, and I don't know
which behaviour is more common.
This makes mapping resilient against whether we would have received a
MapNotify message on override-redirect window. On override-redirect
windows, we immediately trigger the code that would run in the future
MapNotify handler, and ignore it in the future MapNotify message if it
is already run.
BUG=381732
Review URL: https://codereview.chromium.org/1896363004
Cr-Commit-Position: refs/heads/master@{#389572}
2 files changed
