--- a/layout/style/test/file_animations_effect_timing_enddelay.html
+++ b/layout/style/test/file_animations_effect_timing_enddelay.html
@@ -117,32 +117,29 @@ addAsyncAnimTest(async function() {
   advance_clock(400);
   await waitForPaints();
   omta_is(div, "transform", { tx: 40 }, RunningOn.Compositor,
           "Animation is updated on compositor " +
           "duration 1000, endDelay -500, fill forwards, current time 400");
 
   advance_clock(100);
   await waitForPaints();
-  // Bug 1352336: The following should be RunningOn.MainThread
-  omta_is(div, "transform", { tx: 50 }, RunningOn.Either,
+  omta_is(div, "transform", { tx: 50 }, RunningOn.MainThread,
           "Animation is updated on main thread " +
           "duration 1000, endDelay -500, fill forwards, current time 500");
 
   advance_clock(400);
   await waitForPaints();
-  // Bug 1352336: The following should be RunningOn.MainThread
-  omta_is(div, "transform", { tx: 50 }, RunningOn.Either,
+  omta_is(div, "transform", { tx: 50 }, RunningOn.MainThread,
           "Animation is updated on main thread " +
           "duration 1000, endDelay -500, fill forwards, current time 900");
 
   advance_clock(100);
   await waitForPaints();
-  // Bug 1352336: The following should be RunningOn.MainThread
-  omta_is(div, "transform", { tx: 50 }, RunningOn.Either,
+  omta_is(div, "transform", { tx: 50 }, RunningOn.MainThread,
           "Animation is updated on main thread " +
           "duration 1000, endDelay -500, fill forwards, current time 1000");
 
   done_div();
 });
 
 </script>
 </body>

--- a/layout/style/test/file_animations_iterationstart.html
+++ b/layout/style/test/file_animations_iterationstart.html
@@ -45,17 +45,16 @@ addAsyncAnimTest(async function() {
   omta_is(div, "transform", { tx: 50 }, RunningOn.Compositor, "Start of Animation");
 
   advance_clock(4000);
   await waitForPaints();
   omta_is(div, "transform", { tx: 90 }, RunningOn.Compositor, "40% of Animation");
 
   advance_clock(6000);
   await waitForPaints();
-  // Bug 1352336: The following should be RunningOn.MainThread
-  omta_is(div, "transform", { tx: 50 }, RunningOn.Either, "End of Animation");
+  omta_is(div, "transform", { tx: 50 }, RunningOn.MainThread, "End of Animation");
 
   done_div();
 });
 
 </script>
 </body>
 </html>

--- a/layout/style/test/file_animations_playbackrate.html
+++ b/layout/style/test/file_animations_playbackrate.html
@@ -56,18 +56,17 @@ addAsyncAnimTest(async function() {
   var animation = div.getAnimations()[0];
   advance_clock(300);
   await waitForPaints();
 
   animation.playbackRate = 0;
 
   await waitForPaintsFlushed();
 
-  // Bug 1352336: The following should be RunningOn.MainThread
-  omta_is(div, "transform", { tx: 3 }, RunningOn.Either,
+  omta_is(div, "transform", { tx: 3 }, RunningOn.MainThread,
           "animation with zero playback rate should stay in the " +
           "same position and be running on the main thread");
 
   done_div();
 });
 
 addAsyncAnimTest(async function() {
   var [ div, cs ] = new_div("animation: anim 10s 1s");

--- a/layout/style/test/mochitest.ini
+++ b/layout/style/test/mochitest.ini
@@ -48,17 +48,16 @@ skip-if = stylo # bug 1339656
 [test_animations.html]
 skip-if = (toolkit == 'android')
 [test_animations_async_tests.html]
 support-files = Ahem.ttf file_animations_async_tests.html
 [test_animations_dynamic_changes.html]
 [test_animations_effect_timing_duration.html]
 support-files = file_animations_effect_timing_duration.html
 [test_animations_effect_timing_enddelay.html]
-skip-if = true # bug 1352336
 support-files = file_animations_effect_timing_enddelay.html
 [test_animations_effect_timing_iterations.html]
 support-files = file_animations_effect_timing_iterations.html
 [test_animations_event_order.html]
 [test_animations_event_handler_attribute.html]
 [test_animations_iterationstart.html]
 support-files = file_animations_iterationstart.html
 [test_animations_omta.html]