The event filter is only used to let Qt compose a QKeyEvent from an
x11 event for grabbed key events. On Wayland we don't need it as we
can generate good QKeyEvents ourself. This means less event processing
as the events no longer need to pass through the
Workspace::workspaceEvent.
In addition it fixes a regression in LockScreenTest::testEffectsKeyboard
caused by the LockScreenEventFilter sending a QKeyEvent to KSldApp.
This event got intercepted by the global event filter making the test
rightfully fail.
All of kwin except the main function goes into a new (private) library
called kwin. Two new kdeinit_executables are created:
* kwin_x11
* kwin_wayland
Both only use a dedicated main_x11.cpp and main_wayland.cpp with the
main function and a KWin::Application subclass and linking the new
kwin library.
The main idea behind this is to be able to perform more sane sanity
checks. E.g. on Wayland we don't need to first test whether we can
create an X11 connection. Instead we should abort if we cannot connect
to the Wayland display. Also the multi-head checks are not needed on
Wayland, etc. etc. As most of that code is in the main function to
simplify it's better to split.
This will also make it easier to diverge more easily in future. The
Wayland variant can introduce more suited command line arguments for
example. This already started by having the --replace option only
available in X11 variant. The Wayland backend is still a window manager,
but doesn't claim the manager selection.
