Refactor of various layout tests to use RAF

LayoutTests/fast/forms/form-request-autocomplete.html

Index: LayoutTests/fast/forms/form-request-autocomplete.html
diff --git a/LayoutTests/fast/forms/form-request-autocomplete.html b/LayoutTests/fast/forms/form-request-autocomplete.html
index 7c3b99a9b245e3a96c71765cf3a804f081602114..4f5fcc722a89feb139c606881309f4f52d210793 100644
--- a/LayoutTests/fast/forms/form-request-autocomplete.html
+++ b/LayoutTests/fast/forms/form-request-autocomplete.html
@@ -47,10 +47,10 @@ function checkNonUserGesture()
     checkForEnumerableProperties(form);
     form.onautocompleteerror = errorWithReason('disabled');
 
-    setTimeout(function()
+    requestAnimationFrame(function()
     {
         form.requestAutocomplete();
-    }, 0);
+    });
 }
 
 function checkParsedAttributes()