Bug 1378814 - Don't return None in get_pseudo_style if not probing. r=emilio

MozReview-Commit-ID: 5CziNBwYZSa --HG-- extra : rebase_source : b9f25db83e8f82562b78b3b9f3801d484e4d7512
2017-07-07 16:02:17 +10:00 · 2017-07-07 16:02:17 +10:00 · d821a177db
--- a/layout/style/crashtests/1378814.html
+++ b/layout/style/crashtests/1378814.html
@ -0,0 +1,4 @@
+<!DOCTYPE html>
+<script>
+getComputedStyle(document.documentElement, '::first-letter').display;
+</script>
--- a/layout/style/crashtests/crashtests.list
+++ b/layout/style/crashtests/crashtests.list
@ -177,3 +177,4 @@ load content-only-on-visited-before.html
 load 1375812-1.html
 load 1377053-1.html
 load 1377256-1.html
+load 1378814.html