Bug 1141710, part 12 - Check that the hold time is updated when the startTime is set to null. r=birtles

dom/animation/test/css-animations/test_animation-player-starttime.html

@@ -567,12 +567,17 @@ async_test(function(t) {
 
   var player = div.getAnimationPlayers()[0];
 
+  var storedCurrentTime;
+
   player.ready.then(t.step_func(function() {
+    storedCurrentTime = player.currentTime;
     player.startTime = null;
     return player.ready;
   })).catch(t.step_func(function(reason) {
     assert_unreached(reason);
   })).then(function() {
+    assert_equals(player.currentTime, storedCurrentTime,
+      'Test that hold time is correct');
     t.done();
   });
 }, 'Setting startTime to null');