[clutter] cogl: reset pending swaps counter on unrealize

[Lionel Landwerlin <llandwerlin src gnome org>]

commit 0e7b18832a6c694fd2443abeecf91fefc47ee76e
Author: Lionel Landwerlin <llandwerlin gmail com>
Date:   Tue Sep 15 00:32:05 2015 +0100

    cogl: reset pending swaps counter on unrealize
    
    When removing the frame callback on the CoglOnscreen, we loose the ability
    to get notified of swap events. This could leave us with a counter != 0
    which leads to a deadlock situation after the next realize/draw cycle.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=755014

 clutter/cogl/clutter-stage-cogl.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/clutter/cogl/clutter-stage-cogl.c b/clutter/cogl/clutter-stage-cogl.c
index fd51e07..a94e082 100644
--- a/clutter/cogl/clutter-stage-cogl.c
+++ b/clutter/cogl/clutter-stage-cogl.c
@@ -77,6 +77,8 @@ clutter_stage_cogl_unrealize (ClutterStageWindow *stage_window)
       cogl_object_unref (stage_cogl->onscreen);
       stage_cogl->onscreen = NULL;
     }
+
+  stage_cogl->pending_swaps = 0;
 }
 
 static void