Use auto as the initial value for view-timeline-inset.

Per the proposal in https://github.com/w3c/csswg-drafts/issues/7747,
we change view-timeline-inset to have an initial value of auto.

Differential Revision: https://phabricator.services.mozilla.com/D173487

bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1824246
gecko-commit: 7b0a3e4d754ab19861a6507c0d9ec156c147e152
gecko-reviewers: emilio
diff --git a/scroll-animations/css/view-timeline-inset-computed.html b/scroll-animations/css/view-timeline-inset-computed.html
index 77683a4..d9e1c9d 100644
--- a/scroll-animations/css/view-timeline-inset-computed.html
+++ b/scroll-animations/css/view-timeline-inset-computed.html
@@ -13,10 +13,10 @@
   <div id=target></div>
 </div>
 <script>
-test_computed_value('view-timeline-inset', 'initial', '0px');
+test_computed_value('view-timeline-inset', 'initial', 'auto');
 test_computed_value('view-timeline-inset', 'inherit', '1px 2px, auto 3px');
-test_computed_value('view-timeline-inset', 'unset', '0px');
-test_computed_value('view-timeline-inset', 'revert', '0px');
+test_computed_value('view-timeline-inset', 'unset', 'auto');
+test_computed_value('view-timeline-inset', 'revert', 'auto');
 test_computed_value('view-timeline-inset', '1px');
 test_computed_value('view-timeline-inset', '1%');
 test_computed_value('view-timeline-inset', 'calc(1% + 1px)');