Summary:
This change introduces a dedicated X11EventFilter for the mouse
interception on X11. The filter gets created together with the start
of mouse interception and destroyed again when the mouse interception
ends. Thus we don't need to check for each event like it was the case
so far.
Unfortunately the existing methods cannot be removed (yet) as they are
still used by TabBox. Needs investigation whether this is actually
needed.
Test Plan: Xephyr+kwin_x11+Present Windows
Reviewers: #kwin, #plasma
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D7842
Martin Flöser