Avoid animation-iteration-event test timeout

Force a style calclation before setting webkitAnimationName in
animation-iteration-event-destroy-renderer.html

Otherwise the animation may be considered to have already completed
before event listeners were added.

BUG=936462

Change-Id: I5db698db48fe8d029079b144c31673abcef2550a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1623725
Commit-Queue: Eric Willigers <ericwilligers@chromium.org>
Auto-Submit: Eric Willigers <ericwilligers@chromium.org>
Reviewed-by: Stephen McGruer <smcgruer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#662598}

third_party/blink/web_tests/TestExpectations

@@ -1742,8 +1742,6 @@ crbug.com/518987 http/tests/xmlhttprequest/navigation-abort-detaches-frame.html
 
 crbug.com/432129 html/marquee/marquee-scroll.html [ Failure Pass ]
 crbug.com/326139 crbug.com/390125 media/video-frame-accurate-seek.html [ Failure Pass ]
-crbug.com/936462 virtual/threaded/animations/stability/animation-iteration-event-destroy-renderer.html [ Pass Timeout ]
-crbug.com/936462 virtual/disable-blink-gen-property-trees/animations/stability/animation-iteration-event-destroy-renderer.html [ Skip ]
 crbug.com/421283 html/marquee/marquee-scrollamount.html [ Pass Failure ]
 
 # TODO(oshima): Mac Android are currently not supported.

third_party/blink/web_tests/animations/stability/animation-iteration-event-destroy-renderer.html

@@ -18,6 +18,7 @@
   <script src="../../resources/testharness.js"></script>
   <script src="../../resources/testharnessreport.js"></script>
   <script type="text/javascript" charset="utf-8">
+    'use strict';
     var test = async_test("Tests element removal and hiding within the webkitAnimationIteration event handler. Should not crash");
 
     var numDone = 0;
@@ -35,13 +36,15 @@
     function startTest()
     {
       var box1 = document.getElementById('box1');
+      var box2 = document.getElementById('box2');
+      box2.offsetTop; // force style recalc
+
       box1.addEventListener('webkitAnimationIteration', function() {
         box1.parentNode.removeChild(box1);
         animationIterated();
       }, false);
       box1.style.webkitAnimationName = 'move';
 
-      var box2 = document.getElementById('box2');
       box2.addEventListener('webkitAnimationIteration', function() {
         box2.style.display = 'none';
         animationIterated();