Convert IntersectionObserver tests to use testRunner.runIdleTasks.

third_party/WebKit/LayoutTests/http/tests/intersection-observer/iframe-cross-origin.html

Index: third_party/WebKit/LayoutTests/http/tests/intersection-observer/iframe-cross-origin.html
diff --git a/third_party/WebKit/LayoutTests/http/tests/intersection-observer/iframe-cross-origin.html b/third_party/WebKit/LayoutTests/http/tests/intersection-observer/iframe-cross-origin.html
index 0132d6d54395c29b71f9ac6790f139d8ed5ea39a..ef4e39543e893e78c0f0f76a6b009adfa736eec0 100644
--- a/third_party/WebKit/LayoutTests/http/tests/intersection-observer/iframe-cross-origin.html
+++ b/third_party/WebKit/LayoutTests/http/tests/intersection-observer/iframe-cross-origin.html
@@ -10,6 +10,17 @@ self.jsTestIsAsync = true;
 
 description("Simple intersection observer test with no explicit root and target in a cross-origin iframe.");
 
+function waitForNotification(f) {
+  requestAnimationFrame(() => {
+    setTimeout(() => {
+      if (self.testRunner)
+        testRunner.runIdleTasks(f);
+      else
+        requestIdleCallback(f);
+    })

[Sami, 2016/05/18 10:07:23]

nit: missing ';' (in other copy too)

I guess there's no easy way to avoid having this copy of the function?

[szager1, 2016/05/18 21:25:27]

Done.
 
I went ahead and move helper-functions.js into LayoutTests/resources, so it can
be used from http/tests, so no more redundant copies of that stuff.

+  });
+}
+
 var iframe = document.getElementById("target-iframe");
 var actual;
 
@@ -49,23 +60,20 @@ function checkData(actualData, expected) {
 function handleMessage(event) {
   if (event.data.hasOwnProperty('scrollTo')) {
     document.scrollingElement.scrollTop = event.data.scrollTo;
-    requestAnimationFrame(function () { iframe.contentWindow.postMessage("", "*") });
+    waitForNotification(() => { iframe.contentWindow.postMessage("", "*") });
   } else if (event.data.hasOwnProperty('actual')) {
     checkData(event.data.actual, event.data.expected);
   } else if (event.data.hasOwnProperty('DONE')) {
     finishJSTest();
     document.scrollingElement.scrollTop = 0;
   } else {
-    requestAnimationFrame(function () { iframe.contentWindow.postMessage("", "*") });
+    waitForNotification(() => { iframe.contentWindow.postMessage("", "*") });
   }
 }
 
 window.addEventListener("message", handleMessage);
 
-iframe.onload = function() {
-  // See LayoutTests/intersection-observer/README for explanation of double RAF.
-  requestAnimationFrame(() => {
-      requestAnimationFrame(() => { iframe.contentWindow.postMessage("", "*") })
-  });
-}
+iframe.onload = (() => {
+  waitForNotification(() => { iframe.contentWindow.postMessage("", "*") });
+});
 </script>