We assumed that a window will be ready after a single roundtrip but
that's actually not guaranteed by the XDG shell protocol.
This patch waits for an arbitrary timeout (10s) before erroring out and
forcefully closing the window. Since this exercised quite some code
paths, it also reworks some window handling logic and fixes a bunch of
synchronization issues.
(cherry picked from commit eb680bc8c3e4a811dc8736716fd9cf57567c21dd)
Dery Almas
c563a1f251