Expose getAnimations as function on Document

third_party/WebKit/LayoutTests/animations/multiple-same-name-css-animations.html

 <script src="../resources/testharness.js"></script>
 <script src="../resources/testharnessreport.js"></script>
 <style>
 @keyframes a {}
 @keyframes b {}
 </style>
 <div id="target"></div>
 <script>
 function setAnimationProperty(value) {
   target.style.animation = value;
   target.offsetTop;
 }
 
 function getAnimations() {
-  return document.timeline.getAnimations();
+  return document.getAnimations();
 }
 
 function clearAnimations() {
   setAnimationProperty('none');
   assert_equals(getAnimations().length, 0);
 }
 
 test(() => {
   clearAnimations();
   setAnimationProperty('a 1000ms 1500ms forwards, a 2000ms 2500ms backwards, a 3000ms 3500ms both');
@@ skipping 104 matching lines @@
   assert_equals(animations[0].currentTime, 1000);
   assert_equals(animations[0].effect.timing.duration, 3500);
 
   assert_equals(animations[1].currentTime, 2000);
   assert_equals(animations[1].effect.timing.duration, 2500);
 
   assert_equals(animations[2].currentTime, 0);
   assert_equals(animations[2].effect.timing.duration, 1500);
 }, 'Adding same animation names should start additional animations from the end of the name list.');
 </script>