The following layout test is flaky on platform GTK
When it fails gives the following result:
@@ -5,7 +5,7 @@
Testing value of 'disabled' prior to load just after setting them
PASS mainSheetLink.sheet is non-null.
-PASS alternateSheetLink.sheet is null
+FAIL alternateSheetLink.sheet should be null. Was [object CSSStyleSheet].
PASS mainSheetLink.disabled is true
PASS alternateSheetLink.disabled is false
Testing the values when the alternate sheet is loaded (as this is the only one that has sheet() === null)