Revert of IntersectionObserver: use an idle callback to send notifications.

third_party/WebKit/LayoutTests/intersection-observer/timestamp.html

Index: third_party/WebKit/LayoutTests/intersection-observer/timestamp.html
diff --git a/third_party/WebKit/LayoutTests/intersection-observer/timestamp.html b/third_party/WebKit/LayoutTests/intersection-observer/timestamp.html
index fa967660c955e23c89cd5aa59c2eebc1c56b2d3e..47f1dcc5cef50b539b05b8a32e2801154e17682c 100644
--- a/third_party/WebKit/LayoutTests/intersection-observer/timestamp.html
+++ b/third_party/WebKit/LayoutTests/intersection-observer/timestamp.html
@@ -8,8 +8,6 @@
 description("Test that intersection observer time is relative to time in the callback context.");
 var topWindowEntries = [];
 var iframeWindowEntries = [];
-var topWindowObserver;
-var iframeWindowObserver;
 var targetIframe;
 var iframeScroller;
 var topWindowTime;
@@ -17,36 +15,36 @@
 var timestampTolerance = 24;  // 1.5 times frame duration.
 
 function step0() {
-  // Test results are only significant if there's a sufficient gap between
-  // top window time and iframe window time.
-  topWindowTime = performance.now();
-  iframeWindowTime = targetIframe.contentWindow.performance.now();
-  shouldBeGreaterThan("topWindowTime - iframeWindowTime", "2 * timestampTolerance");
+  setTimeout(function() {
+    // Test results are only significant if there's a sufficient gap between
+    // top window time and iframe window time.
+    topWindowTime = performance.now();
+    iframeWindowTime = targetIframe.contentWindow.performance.now();
+    shouldBeGreaterThan("topWindowTime - iframeWindowTime", "2 * timestampTolerance");
 
-  topWindowEntries = topWindowEntries.concat(topWindowObserver.takeRecords());
-  iframeWindowEntries = iframeWindowEntries.concat(iframeWindowObserver.takeRecords());
-  shouldBeEqualToNumber("topWindowEntries.length", 0);
-  shouldBeEqualToNumber("iframeWindowEntries.length", 0);
-  document.scrollingElement.scrollTop = 200;
-  iframeScroller.scrollTop = 250;
-  requestAnimationFrame(step1);
+    shouldBeEqualToNumber("topWindowEntries.length", 0);
+    shouldBeEqualToNumber("iframeWindowEntries.length", 0);
+    document.scrollingElement.scrollTop = 200;
+    iframeScroller.scrollTop = 250;
+    requestAnimationFrame(step1);
+  });
 }
 
 function step1() {
-  topWindowEntries = topWindowEntries.concat(topWindowObserver.takeRecords());
-  iframeWindowEntries = iframeWindowEntries.concat(iframeWindowObserver.takeRecords());
-  topWindowTime = performance.now();
-  iframeWindowTime = targetIframe.contentWindow.performance.now();
-  shouldBeEqualToNumber("topWindowEntries.length", 1);
-  if (topWindowEntries.length) {
-    shouldBeCloseTo("topWindowEntries[0].time", "topWindowTime", timestampTolerance);
-  }
-  shouldBeEqualToNumber("iframeWindowEntries.length", 1);
-  if (iframeWindowEntries.length) {
-    shouldBeCloseTo("iframeWindowEntries[0].time", "iframeWindowTime", timestampTolerance);
-  }
-  finishJSTest();
-  document.scrollingElement.scrollTop = 0;
+  setTimeout(function() {
+    topWindowTime = performance.now();
+    iframeWindowTime = targetIframe.contentWindow.performance.now();
+    shouldBeEqualToNumber("topWindowEntries.length", 1);
+    if (topWindowEntries.length) {
+      shouldBeCloseTo("topWindowEntries[0].time", "topWindowTime", timestampTolerance);
+    }
+    shouldBeEqualToNumber("iframeWindowEntries.length", 1);
+    if (iframeWindowEntries.length) {
+      shouldBeCloseTo("iframeWindowEntries[0].time", "iframeWindowTime", timestampTolerance);
+    }
+    finishJSTest();
+    document.scrollingElement.scrollTop = 0;
+  });
 }
 
 function runTest() {
@@ -55,19 +53,18 @@
 
   // Observer created here, callback created in iframe context.  Timestamps should be
   // from this window.
-  topWindowObserver = new IntersectionObserver(targetIframe.contentDocument.createObserverCallback(topWindowEntries), {});
-  topWindowObserver.observe(target);
+  var observer = new IntersectionObserver(targetIframe.contentDocument.createObserverCallback(topWindowEntries), {});
+  observer.observe(target);
 
   // Callback created here, observer created in iframe.  Timestamps should be
   // from iframe window.
-  iframeWindowObserver = targetIframe.contentDocument.createObserver(function(newEntries) {
+  observer = targetIframe.contentDocument.createObserver(function(newEntries) {
     for (var i = 0; i < newEntries.length; i++)
       iframeWindowEntries.push(newEntries[i]);
   });
-  iframeWindowObserver.observe(target);
+  observer.observe(target);
 
-  // See README for explanation of double RAF.
-  requestAnimationFrame(() => { requestAnimationFrame(step0) });
+  step0();
 }
 
 window.onload = function() {