backend: Set up and use ownership chains

This means objects have an owner, where the chain eventually always
leads to a MetaContext. This also means that all objects can find their
way to other object instances via the chain, instead of scattered global
singletons.

This is a squashed commit originally containing the following:

cursor-tracker: Don't get backend from singleton

idle-manager: Don't get backend from singleton

input-device: Pass pointer to backend during construction

The backend is needed during construction to get the wacom database.

input-mapper: Pass backend when constructing

monitor: Don't get backend from singleton

monitor-manager: Get backend directly from monitor manager

remote: Get backend from manager class

For the remote desktop and screen cast implementations, replace getting
the backend from singletons with getting it via the manager classes.

launcher: Pass backend during construction

device-pool: Pass backend during construction

Instead of passing the (maybe null) launcher, pass the backend, and get
the launcher from there. That way we always have a way to some known
context from the device pool.

drm-buffer/gbm: Get backend via device pool

cursor-renderer: Get backend directly from renderer

input-device: Get backend getter

input-settings: Add backend construct property and getter

input-settings/x11: Don't get backend from singleton

renderer: Get backend from renderer itself

seat-impl: Add backend getter

seat/native: Get backend from instance struct

stage-impl: Get backend from stage impl itself

x11/xkb-a11y: Don't get backend from singleton

backend/x11/nested: Don't get Wayland compositor from singleton

crtc: Add backend property

Adding a link to the GPU isn't enough; the virtual CRTCs of virtual
monitors doesn't have one.

cursor-tracker: Don't get display from singleton

remote: Don't get display from singleton

seat: Don't get display from singleton

backend/x11: Don't get display from singleton

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2718>

1 files changed, 14 insertions, 4 deletions

diff --git a/src/backends/native/meta-launcher.c b/src/backends/native/meta-launcher.c
index e968baeed..da202ed31 100644
--- a/src/backends/native/meta-launcher.c
+++ b/src/backends/native/meta-launcher.c
@@ -46,6 +46,8 @@
 
 struct _MetaLauncher
 {
+  MetaBackend *backend;
+
   MetaDbusLogin1Session *session_proxy;
   MetaDbusLogin1Seat *seat_proxy;
   char *seat_id;
@@ -309,7 +311,7 @@ get_seat_proxy (gchar        *seat_id,
 static void
 sync_active (MetaLauncher *self)
 {
-  MetaBackend *backend = meta_get_backend ();
+  MetaBackend *backend = self->backend;
   MetaBackendNative *backend_native = META_BACKEND_NATIVE (backend);
   MetaDbusLogin1Session *session_proxy = self->session_proxy;
   gboolean active;
@@ -371,9 +373,10 @@ meta_launcher_get_session_proxy (MetaLauncher *launcher)
 }
 
 MetaLauncher *
-meta_launcher_new (const char  *fallback_session_id,
-                   const char  *fallback_seat_id,
-                   GError     **error)
+meta_launcher_new (MetaBackend  *backend,
+                   const char   *fallback_session_id,
+                   const char   *fallback_seat_id,
+                   GError      **error)
 {
   MetaLauncher *self = NULL;
   g_autoptr (MetaDbusLogin1Session) session_proxy = NULL;
@@ -420,6 +423,7 @@ meta_launcher_new (const char  *fallback_session_id,
     goto fail;
 
   self = g_new0 (MetaLauncher, 1);
+  self->backend = backend;
   self->session_proxy = g_object_ref (session_proxy);
   self->seat_proxy = g_object_ref (seat_proxy);
   self->seat_id = g_steal_pointer (&seat_id);
@@ -455,3 +459,9 @@ meta_launcher_activate_vt (MetaLauncher  *launcher,
   return meta_dbus_login1_seat_call_switch_to_sync (launcher->seat_proxy, vt,
                                                     NULL, error);
 }
+
+MetaBackend *
+meta_launcher_get_backend (MetaLauncher *launcher)
+{
+  return launcher->backend;
+}