Fix flakiness in v/t/fast/compositorworker/basic-plumbing-main-to-worker.html

third_party/WebKit/LayoutTests/virtual/threaded/fast/compositorworker/basic-plumbing-main-to-worker.html

Index: third_party/WebKit/LayoutTests/virtual/threaded/fast/compositorworker/basic-plumbing-main-to-worker.html
diff --git a/third_party/WebKit/LayoutTests/virtual/threaded/fast/compositorworker/basic-plumbing-main-to-worker.html b/third_party/WebKit/LayoutTests/virtual/threaded/fast/compositorworker/basic-plumbing-main-to-worker.html
index adf005ae59ee43e350317be0c4c87d4b97ce77c3..109b8ac5d06ad5913f8017469d90cb87dac38a65 100644
--- a/third_party/WebKit/LayoutTests/virtual/threaded/fast/compositorworker/basic-plumbing-main-to-worker.html
+++ b/third_party/WebKit/LayoutTests/virtual/threaded/fast/compositorworker/basic-plumbing-main-to-worker.html
@@ -58,9 +58,12 @@ function updateElementAndVerify(e) {
     test.done();
   });
 
-  // Delay posting to the compositor until we have had another frame (i.e. commit).
-  requestAnimationFrame(function() {
-    worker.postMessage({});
+  // Delay posting to the compositor until we have had two frames to ensure our change
+  // is activated on the compositor.
+  requestAnimationFrame(function(){
+    requestAnimationFrame(function() {
+      worker.postMessage({});
+    });
   });
 }
 </script>