[gnome-shell] environment: Try harder to find a transition

[Florian Müllner <fmuellner src gnome org>]

commit b6754d7db7f4522c336158fafe6f469fc8263b1b
Author: Florian Müllner <fmuellner gnome org>
Date:   Fri Sep 20 02:50:36 2019 +0200

    environment: Try harder to find a transition
    
    When easing, we need the transition of one of the involved properties
    to connect our callbacks. Currently we simply get the transition for
    the first property, however as Clutter optimizes the case where a
    property doesn't actually change, that transition may be NULL even
    though we still animate other properties.
    
    So instead of only looking at the transition of the first property,
    try to find a transition for any of the involved properties.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/issues/1572

 js/ui/environment.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/js/ui/environment.js b/js/ui/environment.js
index 1f9420035d..38d1d281a6 100644
--- a/js/ui/environment.js
+++ b/js/ui/environment.js
@@ -121,7 +121,9 @@ function _easeActor(actor, params) {
     actor.set(params);
     actor.restore_easing_state();
 
-    let transition = actor.get_transition(animatedProps[0]);
+    let transition = animatedProps.map(p => actor.get_transition(p))
+        .find(t => t !== null);
+
     if (transition)
         transition.connect('stopped', (t, finished) => callback(finished));
     else