diff --git a/gfx/layers/apz/test/mochitest/test_scroll_inactive_bug1190112.html b/gfx/layers/apz/test/mochitest/test_scroll_inactive_bug1190112.html
index b4a3a081f398..0868ffe73379 100644
--- a/gfx/layers/apz/test/mochitest/test_scroll_inactive_bug1190112.html
+++ b/gfx/layers/apz/test/mochitest/test_scroll_inactive_bug1190112.html
@@ -536,6 +536,7 @@ window.onload = function() {
   });
 }
 
+SimpleTest.testInChaosMode();
 SimpleTest.waitForExplicitFinish();
 </script>
 </body>
diff --git a/gfx/layers/apz/test/mochitest/test_scroll_inactive_flattened_frame.html b/gfx/layers/apz/test/mochitest/test_scroll_inactive_flattened_frame.html
index 464e92bd6779..a23ac1def72e 100644
--- a/gfx/layers/apz/test/mochitest/test_scroll_inactive_flattened_frame.html
+++ b/gfx/layers/apz/test/mochitest/test_scroll_inactive_flattened_frame.html
@@ -44,6 +44,7 @@ window.onload = function() {
   });
 }
 
+SimpleTest.testInChaosMode();
 SimpleTest.waitForExplicitFinish();
 </script>
 </body>