Runner/Windows make the window finding more reliable
Summary:
QTimer::singleShot could dispatch gatherInfo after the next WindowsRunner::match was called in a not-ready state preventing to return match.
prepareForMatchSession will lock the lock, allowing only gatherInfo to run, which will unlock the lock, allowing match() to run.
BUG: 414804
FIXED-IN: 5.18
Reviewers: Plasma, ngraham, mart, davidedmundson
Subscribers: plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D26494