The FullscreenShell is a Wayland protocol provided by Weston to have
exactly one surface per output. This is exactly what KWin needs. So
in case the Wayland server we connect to provides the FullscreenShell
we prefer it over the normal Shell and mapping our surface as fullscreen.
The protocol is not yet part of wayland-client library, so the header
and source file needs to be generated. This is done during the build
process using the external tool wayland-scanner. The protocol
description is copied from the Westion 1.5 sources.
REVIEW: 119839
The Wayland::Registry class wraps wl_registry handling. It keeps track
of the interfaces in the registry and emits signals whenever a known
interface gets announced or removed. So far it only tracks the interfaces
which are used and needed by KWin.
The Wayland event queue is moved into a dedicated thread and a
new class is created for just creating the connection and listening
for events. The WaylandBackend creates the thread and uses an event
queue for the main thread.
REVIEW: 119761
