[gnome-multi-writer] Use G_DECLARE_DERIVABLE_TYPE

[Richard Hughes <rhughes src gnome org>]

commit 8012c8fa12225825a3b810ea2a8f49b8c692b056
Author: Richard Hughes <richard hughsie com>
Date:   Tue Jul 19 09:19:33 2016 +0100

    Use G_DECLARE_DERIVABLE_TYPE

 src/gmw-device.h |   12 ++----------
 1 files changed, 2 insertions(+), 10 deletions(-)
---
diff --git a/src/gmw-device.h b/src/gmw-device.h
index af0b7a5..f76abf0 100644
--- a/src/gmw-device.h
+++ b/src/gmw-device.h
@@ -27,16 +27,8 @@
 #include <gusb.h>
 #include <udisks/udisks.h>
 
-typedef struct _GmwDevice      GmwDevice;
-typedef struct _GmwDeviceClass GmwDeviceClass;
-
-#define GMW_TYPE_DEVICE                (gmw_device_get_type ())
-#define GMW_DEVICE(o)          (G_TYPE_CHECK_INSTANCE_CAST ((o), GMW_TYPE_DEVICE, GmwDevice))
-#define GMW_IS_DEVICE(o)       (G_TYPE_CHECK_INSTANCE_TYPE ((o), GMW_TYPE_DEVICE))
-
-struct _GmwDevice {
-       GObject          parent_instance;
-};
+#define GMW_TYPE_DEVICE (gmw_device_get_type ())
+G_DECLARE_DERIVABLE_TYPE (GmwDevice, gmw_device, GMW, DEVICE, GObject)
 
 struct _GmwDeviceClass {
        GObjectClass     parent_class;