ivi-shell: add_screen_remove_layer API

It is analagous to layer_remove_surface API.
The API removes a layer from the render order
of the screen.

v3:
add the new vfunc at the end of
the ivi_layout_interface struct.

Signed-off-by: Emre Ucan <eucan@de.adit-jv.com>
Reviewed-by: Eugen Friedrich <friedrix@gmail.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
diff --git a/ivi-shell/ivi-layout-export.h b/ivi-shell/ivi-layout-export.h
index 2317d6e..39ffde1 100644
--- a/ivi-shell/ivi-layout-export.h
+++ b/ivi-shell/ivi-layout-export.h
@@ -578,6 +578,16 @@
 	 */
 	struct ivi_layout_surface *
 		(*get_surface)(struct weston_surface *surface);
+
+	/**
+	 * \brief Remove a ivi_layer to a weston_output which is currently managed
+	 * by the service
+	 *
+	 * \return IVI_SUCCEEDED if the method call was successful
+	 * \return IVI_FAILED if the method call was failed
+	 */
+	int32_t (*screen_remove_layer)(struct weston_output *output,
+				       struct ivi_layout_layer *removelayer);
 };
 
 #ifdef __cplusplus