backends: Update stage views and stage dimension from MetaStage

This reduces the amount of code duplication between the native and
nested backend.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4331>

src/backends/meta-stage-impl-private.h

@@ -65,4 +65,6 @@ MetaBackend * meta_stage_impl_get_backend (MetaStageImpl *stage_impl);
 void meta_stage_impl_add_onscreen_frame_info (MetaStageImpl    *stage_impl,
                                               ClutterStageView *view);
 
+void meta_stage_impl_rebuild_views (MetaStageImpl *stage_impl);
+
 G_END_DECLS

src/backends/meta-stage-impl.c

@@ -34,6 +34,7 @@
 #include <stdlib.h>
 #include <math.h>
 
+#include "backends/meta-renderer.h"
 #include "backends/meta-stage-view-private.h"
 #include "clutter/clutter-mutter.h"
 #include "cogl/cogl.h"
@@ -900,3 +901,14 @@ meta_stage_impl_get_backend (MetaStageImpl *stage_impl)
 
   return priv->backend;
 }
+
+void
+meta_stage_impl_rebuild_views (MetaStageImpl *stage_impl)
+{
+  MetaBackend *backend = meta_stage_impl_get_backend (stage_impl);
+  MetaRenderer *renderer = meta_backend_get_renderer (backend);
+  ClutterActor *stage = meta_backend_get_stage (backend);
+
+  meta_renderer_rebuild_views (renderer);
+  clutter_stage_clear_stage_views (CLUTTER_STAGE (stage));
+}

src/backends/meta-stage-private.h

@@ -70,4 +70,6 @@ META_EXPORT_TEST
 void meta_stage_remove_watch (MetaStage      *stage,
                               MetaStageWatch *watch);
 
+void meta_stage_rebuild_views (MetaStage *stage);
+
 G_END_DECLS

src/backends/meta-stage.c

@@ -498,3 +498,19 @@ meta_stage_remove_watch (MetaStage      *stage,
 
   g_assert (removed);
 }
+
+void
+meta_stage_rebuild_views (MetaStage *stage)
+{
+  ClutterStageWindow *stage_window =
+    _clutter_stage_get_window (CLUTTER_STAGE (stage));
+  MetaStageImpl *stage_impl = META_STAGE_IMPL (stage_window);
+  MetaMonitorManager *monitor_manager =
+    meta_backend_get_monitor_manager (stage->backend);
+  int width, height;
+
+  meta_stage_impl_rebuild_views (stage_impl);
+
+  meta_monitor_manager_get_screen_size (monitor_manager, &width, &height);
+  clutter_actor_set_size (CLUTTER_ACTOR (stage), width, height);
+}

src/backends/native/meta-backend-native.c

@@ -400,14 +400,11 @@ static void
 meta_backend_native_update_stage (MetaBackend *backend)
 {
   ClutterActor *stage = meta_backend_get_stage (backend);
-  ClutterStageWindow *stage_window =
-    _clutter_stage_get_window (CLUTTER_STAGE (stage));
-  MetaStageNative *stage_native = META_STAGE_NATIVE (stage_window);
   MetaMonitorManager *monitor_manager =
     meta_backend_get_monitor_manager (backend);
   int width, height;
 
-  meta_stage_native_rebuild_views (stage_native);
+  meta_stage_rebuild_views (META_STAGE (stage));
 
   meta_monitor_manager_get_screen_size (monitor_manager, &width, &height);
   clutter_actor_set_size (stage, width, height);

src/backends/native/meta-stage-native.c

@@ -46,18 +46,6 @@ struct _MetaStageNative
 
 G_DEFINE_FINAL_TYPE (MetaStageNative, meta_stage_native, META_TYPE_STAGE_IMPL)
 
-void
-meta_stage_native_rebuild_views (MetaStageNative *stage_native)
-{
-  MetaStageImpl *stage_impl = META_STAGE_IMPL (stage_native);
-  MetaBackend *backend = meta_stage_impl_get_backend (stage_impl);
-  MetaRenderer *renderer = meta_backend_get_renderer (backend);
-  ClutterActor *stage = meta_backend_get_stage (backend);
-
-  meta_renderer_rebuild_views (renderer);
-  clutter_stage_clear_stage_views (CLUTTER_STAGE (stage));
-}
-
 static gboolean
 meta_stage_native_can_clip_redraws (ClutterStageWindow *stage_window)
 {

src/backends/native/meta-stage-native.h

@@ -28,5 +28,3 @@
 #define META_TYPE_STAGE_NATIVE (meta_stage_native_get_type ())
 G_DECLARE_FINAL_TYPE (MetaStageNative, meta_stage_native,
                       META, STAGE_NATIVE, MetaStageImpl)
-
-void meta_stage_native_rebuild_views (MetaStageNative *stage_native);

src/backends/x11/nested/meta-backend-x11-nested.c

@@ -21,6 +21,7 @@
 
 #include "backends/meta-input-settings-dummy.h"
 #include "backends/meta-monitor-manager-dummy.h"
+#include "backends/meta-stage-private.h"
 #include "backends/x11/nested/meta-backend-x11-nested.h"
 #include "backends/x11/nested/meta-cursor-renderer-x11-nested.h"
 #include "backends/x11/nested/meta-renderer-x11-nested.h"
@@ -98,16 +99,8 @@ static void
 meta_backend_x11_nested_update_stage (MetaBackend *backend)
 {
   ClutterActor *stage = meta_backend_get_stage (backend);
-  MetaRenderer *renderer = meta_backend_get_renderer (backend);
-  MetaMonitorManager *monitor_manager =
-    meta_backend_get_monitor_manager (backend);
-  int width, height;
 
-  meta_renderer_rebuild_views (renderer);
+  meta_stage_rebuild_views (META_STAGE (stage));
-  clutter_stage_clear_stage_views (CLUTTER_STAGE (stage));
-
-  meta_monitor_manager_get_screen_size (monitor_manager, &width, &height);
-  clutter_actor_set_size (stage, width, height);
 }
 
 static void