index desktop views by qscreen instead of id, making ScreenPool
the single source of truth for the mapping between screen names
and ids. This is less error prone and easier to consistency check
(if view->screenToFollow() is ever different to its has key it will
assert)
The whole logic of screen management is moved to ScreenPool.
ShellCorona will have to never call QGuiApp->screens, but only trust what ScreenPool it's telling it
Also adds an autotests on screenpool which makes a fake wayland server which sends screen added/removed/changed events
if we do immediately setPrimaryOutputName, the name is still :0.0
because the app didn't have time to react yet (since here we are in the event filter,
we are just before that by definition) so the output name can still be wrong.
when we go from no outputs to one, at this point the name of the one QScreen
instane is still wrong :0.0 which will be renamed right after.
BUG:447936
when we disconnect all real outputs, we only have a single fake QScreen in this case consider corona to not have screens and remove all desktops and panels. makes easier for a coherent reconstruction when real screens get back and won't save in screen mapping the :0.0 connector name
Refactors XRandr support together with the new Wayland code into a
PrimaryOutputWatcher class.
For X11 it listens to xcb events.
For Wayland it uses the kde_output_management_v2 protocols.
Marco Martin
Aleix Pol