Update webview plugin test to draw three frames, and not force paint.

LayoutTests/plugins/webview-plugin-lifecycle.html

Index: LayoutTests/plugins/webview-plugin-lifecycle.html
diff --git a/LayoutTests/plugins/webview-plugin-lifecycle.html b/LayoutTests/plugins/webview-plugin-lifecycle.html
index a9f3804f4abaad1d356a53f339f68fdd5e851b3d..4175edc795b3c8f266ccdc246c2146c6963403b2 100644
--- a/LayoutTests/plugins/webview-plugin-lifecycle.html
+++ b/LayoutTests/plugins/webview-plugin-lifecycle.html
@@ -11,11 +11,13 @@
 onload = function() {
     if (window.testRunner) {
         window.testRunner.waitUntilDone();
-        // Need to paint two frames in order to allow the plugin to propery load.
+        // Need to paint two frames in order to allow the plugin to properly load.
         // TODO(chrishtr): find out why and fix.
-        window.testRunner.layoutAndPaintAsyncThen(function() {
-            window.testRunner.layoutAndPaintAsyncThen(function() {
-                window.testRunner.notifyDone();
+        requestAnimationFrame(function() {
+            requestAnimationFrame(function() {
+                requestAnimationFrame(function() {
+                    window.testRunner.notifyDone();
+                });
             });
         });
     }