Remove unnecessary RAF from tests.

third_party/WebKit/LayoutTests/intersection-observer/iframe-no-root.html

Index: third_party/WebKit/LayoutTests/intersection-observer/iframe-no-root.html
diff --git a/third_party/WebKit/LayoutTests/intersection-observer/iframe-no-root.html b/third_party/WebKit/LayoutTests/intersection-observer/iframe-no-root.html
index b3552a3b5cf641561d52ff3df664c18b774f17b5..98566e25d9ab774061128180f9668f484515aa04 100644
--- a/third_party/WebKit/LayoutTests/intersection-observer/iframe-no-root.html
+++ b/third_party/WebKit/LayoutTests/intersection-observer/iframe-no-root.html
@@ -21,9 +21,6 @@ targetIframe.onload = function() {
   var observer = new IntersectionObserver(observer_callback, {});
   observer.observe(target);
 
-  // TODO(szager): It shouldn't be necessary to RAF after the call to observer()
-  // and before changing the scroll position, but it is.
-
   function step0() {
     setTimeout(function() {
       shouldBeEqualToNumber("entries.length", 0);
@@ -82,6 +79,6 @@ targetIframe.onload = function() {
     });
   }
 
-  requestAnimationFrame(step0);
+  step0();
 }
 </script>