[PATCH] shell: Fix 2 switcher crashes.

[zhiwen.wu at linux.intel.com]

From: Alex Wu <zhiwen.wu at linux.intel.com>

In case of no regular window, switcher will crash in switch_next()
due to "next == NULL" and in switcher_destroy() due to
"switcher->current == NULL".
---
 src/shell.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/src/shell.c b/src/shell.c
index 765b0a4..28d5ea7 100644
--- a/src/shell.c
+++ b/src/shell.c
@@ -1840,6 +1840,9 @@ switcher_next(struct switcher *switcher)
 	if (next == NULL)
 		next = first;
 
+	if (next == NULL) 
+		return;
+
 	wl_list_remove(&switcher->listener.link);
 	wl_list_insert(next->surface.resource.destroy_listener_list.prev,
 		       &switcher->listener.link);
@@ -1871,7 +1874,8 @@ switcher_destroy(struct switcher *switcher, uint32_t time)
 		weston_surface_damage(surface);
 	}
 
-	activate(compositor->shell, switcher->current, device, time);
+	if (switcher->current)
+		activate(compositor->shell, switcher->current, device, time);
 	wl_list_remove(&switcher->listener.link);
 	wl_input_device_end_keyboard_grab(&device->input_device, time);
 	free(switcher);
-- 
1.7.5.4