[gnome-builder] animation: be a bit more defensive

[Christian Hergert <chergert src gnome org>]

commit 92eb3110523979848c1a9e2b41653dfedc7f2979
Author: Christian Hergert <christian hergert me>
Date:   Thu Nov 20 16:41:39 2014 -0800

    animation: be a bit more defensive

 src/animation/gb-animation.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)
---
diff --git a/src/animation/gb-animation.c b/src/animation/gb-animation.c
index 6d4cd24..f1104d2 100644
--- a/src/animation/gb-animation.c
+++ b/src/animation/gb-animation.c
@@ -548,13 +548,14 @@ static gboolean
 gb_animation_widget_tick_cb (GdkFrameClock *frame_clock,
                              GbAnimation   *animation)
 {
-  gboolean ret;
+  gboolean ret = G_SOURCE_REMOVE;
 
   g_assert (GDK_IS_FRAME_CLOCK (frame_clock));
   g_assert (GB_IS_ANIMATION (animation));
 
-  if (!(ret = gb_animation_tick (animation)))
-    gb_animation_stop (animation);
+  if (animation->priv->tween_handler)
+    if (!(ret = gb_animation_tick (animation)))
+      gb_animation_stop (animation);
 
   return ret;
 }