DevTools: switch Timeline frontend into buffered mode and remove the corresponding experiment.

LayoutTests/inspector/timeline/timeline-animation-frame.html

Index: LayoutTests/inspector/timeline/timeline-animation-frame.html
diff --git a/LayoutTests/inspector/timeline/timeline-animation-frame.html b/LayoutTests/inspector/timeline/timeline-animation-frame.html
index c545b55402f0d11100726d2021a12e623f656932..ddfa1f3335f662d9298a988e5ccef935109542b5 100644
--- a/LayoutTests/inspector/timeline/timeline-animation-frame.html
+++ b/LayoutTests/inspector/timeline/timeline-animation-frame.html
@@ -4,23 +4,20 @@
 <script src="../../http/tests/inspector/timeline-test.js"></script>
 <script>
 
-function performActions()
+function performActions(callback)
 {
     var element = document.getElementById("animation");
     var requestId = window.requestAnimationFrame(animationFrameCallback, element);
     function animationFrameCallback()
     {
         window.cancelAnimationFrame(requestId);
+        callback();
     }
 }
 
 function test()
 {
-    InspectorTest.startTimeline(function() {
-        InspectorTest.evaluateInPage("performActions()");
-    });
-
-    InspectorTest.waitForRecordType("CancelAnimationFrame", finish);
+    InspectorTest.invokeAsyncWithTimeline("performActions", finish);
 
     function finish()
     {