Display call window over the phosh lockscreen

Closes #41

src/wayland/layersurface.h

@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2018 Purism SPC
+ *
+ * SPDX-License-Identifier: GPL-3.0+
+ */
+
+
+/*
+
+WARNING: this file is taken directly from phosh, with no modificaions apart from this message. Please update phosh instead of changing this file. Please copy the file back here afterwards, with the same notice.
+
+*/
+
+
+#pragma once
+
+#include <gtk/gtk.h>
+/* TODO: We use the enum constants from here, use glib-mkenums */
+#include "wlr-layer-shell-unstable-v1-client-protocol.h"
+
+#define PHOSH_TYPE_LAYER_SURFACE                 (phosh_layer_surface_get_type ())
+
+G_DECLARE_DERIVABLE_TYPE (PhoshLayerSurface, phosh_layer_surface, PHOSH, LAYER_SURFACE, GtkWindow)
+
+/**
+ * PhoshLayerSurfaceClass
+ * @parent_class: The parent class
+ */
+struct _PhoshLayerSurfaceClass
+{
+  GtkWindowClass parent_class;
+
+  /* Signals
+   */
+  void (*configured)   (PhoshLayerSurface    *self);
+};
+
+GtkWidget *phosh_layer_surface_new (gpointer layer_shell,
+                                    gpointer wl_output);
+struct     zwlr_layer_surface_v1 *phosh_layer_surface_get_layer_surface(PhoshLayerSurface *self);
+struct     wl_surface            *phosh_layer_surface_get_wl_surface(PhoshLayerSurface *self);