IntersectionObserver: use an idle callback to send notifications.

third_party/WebKit/LayoutTests/intersection-observer/same-document-root.html

Index: third_party/WebKit/LayoutTests/intersection-observer/same-document-root.html
diff --git a/third_party/WebKit/LayoutTests/intersection-observer/same-document-root.html b/third_party/WebKit/LayoutTests/intersection-observer/same-document-root.html
index d96f6d1f09007dd2a565cce24a2a26bd3d7bb260..3c4cfe76f50915b1c25ed89b2da7874e1312f455 100644
--- a/third_party/WebKit/LayoutTests/intersection-observer/same-document-root.html
+++ b/third_party/WebKit/LayoutTests/intersection-observer/same-document-root.html
@@ -9,105 +9,108 @@
 <div style="width:100%;height:700px;"></div>
 
 <script>
-  description("Simple intersection observer test with explicit root and target in the same document.");
-  var target = document.getElementById("target");
-  var root = document.getElementById("root");
-  var entries = [];
+description("Simple intersection observer test with explicit root and target in the same document.");
+var target = document.getElementById("target");
+var root = document.getElementById("root");
+var entries = [];
+var observer = new IntersectionObserver(
+    changes => { entries = entries.concat(changes) },
+    { root: document.getElementById("root") }
+);
 
-  observer_callback = function(changes) {
-    for (var i in changes)
-      entries.push(changes[i]);
-  };
-  var observer = new IntersectionObserver(observer_callback, {"root": document.getElementById("root")});
+onload = function() {
   observer.observe(target);
+  entries = entries.concat(observer.takeRecords());
+  shouldBeEqualToNumber("entries.length", 0);
+  requestAnimationFrame(() => { requestAnimationFrame(step0) });
+}
 
-  // Test that notifications are not generated when the target is overflow clipped by the root.
-  function step0() {
-    setTimeout(function() {
-      shouldBeEqualToNumber("entries.length", 0);
-      document.scrollingElement.scrollTop = 600;
-      requestAnimationFrame(step1);
-    });
-  }
+// Test that notifications are not generated when the target is overflow clipped by the root.
+function step0() {
+  entries = entries.concat(observer.takeRecords());
+  shouldBeEqualToNumber("entries.length", 0);
+  document.scrollingElement.scrollTop = 600;
+  requestAnimationFrame(step1);
+}
 
-  function step1() {
-    setTimeout(function() {
-      shouldBeEqualToNumber("entries.length", 0);
-      root.scrollTop = 150;
-      requestAnimationFrame(step2);
-    });
-  }
+function step1() {
+  entries = entries.concat(observer.takeRecords());
+  shouldBeEqualToNumber("entries.length", 0);
+  root.scrollTop = 150;
+  requestAnimationFrame(step2);
+}
 
-  function step2() {
-    setTimeout(function() {
-      shouldBeEqualToNumber("entries.length", 1);
-      shouldBeEqualToNumber("entries[0].boundingClientRect.left", 11);
-      shouldBeEqualToNumber("entries[0].boundingClientRect.right", 111);
-      shouldBeEqualToNumber("entries[0].boundingClientRect.top", 261);
-      shouldBeEqualToNumber("entries[0].boundingClientRect.bottom", 361);
-      shouldBeEqualToNumber("entries[0].intersectionRect.left", 11);
-      shouldBeEqualToNumber("entries[0].intersectionRect.right", 111);
-      shouldBeEqualToNumber("entries[0].intersectionRect.top", 261);
-      shouldBeEqualToNumber("entries[0].intersectionRect.bottom", 311);
-      shouldBeEqualToNumber("entries[0].rootBounds.left", 11);
-      shouldBeEqualToNumber("entries[0].rootBounds.right", 111);
-      shouldBeEqualToNumber("entries[0].rootBounds.top", 111);
-      shouldBeEqualToNumber("entries[0].rootBounds.bottom", 311);
-      shouldEvaluateToSameObject("entries[0].target", target);
-      document.scrollingElement.scrollTop = 0;
-      requestAnimationFrame(step3);
-    });
+function step2() {
+  entries = entries.concat(observer.takeRecords());
+  shouldBeEqualToNumber("entries.length", 1);
+  if (entries.length > 0) {
+    shouldBeEqualToNumber("entries[0].boundingClientRect.left", 11);
+    shouldBeEqualToNumber("entries[0].boundingClientRect.right", 111);
+    shouldBeEqualToNumber("entries[0].boundingClientRect.top", 261);
+    shouldBeEqualToNumber("entries[0].boundingClientRect.bottom", 361);
+    shouldBeEqualToNumber("entries[0].intersectionRect.left", 11);
+    shouldBeEqualToNumber("entries[0].intersectionRect.right", 111);
+    shouldBeEqualToNumber("entries[0].intersectionRect.top", 261);
+    shouldBeEqualToNumber("entries[0].intersectionRect.bottom", 311);
+    shouldBeEqualToNumber("entries[0].rootBounds.left", 11);
+    shouldBeEqualToNumber("entries[0].rootBounds.right", 111);
+    shouldBeEqualToNumber("entries[0].rootBounds.top", 111);
+    shouldBeEqualToNumber("entries[0].rootBounds.bottom", 311);
+    shouldEvaluateToSameObject("entries[0].target", target);
   }
+  document.scrollingElement.scrollTop = 0;
+  requestAnimationFrame(step3);
+}
 
-  function step3() {
-    setTimeout(function() {
-      shouldBeEqualToNumber("entries.length", 1);
-      root.scrollTop = 0;
-      requestAnimationFrame(step4);
-    });
-  }
+function step3() {
+  entries = entries.concat(observer.takeRecords());
+  shouldBeEqualToNumber("entries.length", 1);
+  root.scrollTop = 0;
+  requestAnimationFrame(step4);
+}
 
-  function step4() {
-    setTimeout(function() {
-      shouldBeEqualToNumber("entries.length", 2);
-      shouldBeEqualToNumber("entries[1].boundingClientRect.left", 11);
-      shouldBeEqualToNumber("entries[1].boundingClientRect.right", 111);
-      shouldBeEqualToNumber("entries[1].boundingClientRect.top", 1011);
-      shouldBeEqualToNumber("entries[1].boundingClientRect.bottom", 1111);
-      shouldBeEqualToNumber("entries[1].intersectionRect.left", 0);
-      shouldBeEqualToNumber("entries[1].intersectionRect.right", 0);
-      shouldBeEqualToNumber("entries[1].intersectionRect.top", 0);
-      shouldBeEqualToNumber("entries[1].intersectionRect.bottom", 0);
-      shouldBeEqualToNumber("entries[1].rootBounds.left", 11);
-      shouldBeEqualToNumber("entries[1].rootBounds.right", 111);
-      shouldBeEqualToNumber("entries[1].rootBounds.top", 711);
-      shouldBeEqualToNumber("entries[1].rootBounds.bottom", 911);
-      shouldEvaluateToSameObject("entries[1].target", target);
-      root.scrollTop = 150;
-      requestAnimationFrame(step5);
-    });
+function step4() {
+  entries = entries.concat(observer.takeRecords());
+  shouldBeEqualToNumber("entries.length", 2);
+  if (entries.length > 1) {
+    shouldBeEqualToNumber("entries[1].boundingClientRect.left", 11);
+    shouldBeEqualToNumber("entries[1].boundingClientRect.right", 111);
+    shouldBeEqualToNumber("entries[1].boundingClientRect.top", 1011);
+    shouldBeEqualToNumber("entries[1].boundingClientRect.bottom", 1111);
+    shouldBeEqualToNumber("entries[1].intersectionRect.left", 0);
+    shouldBeEqualToNumber("entries[1].intersectionRect.right", 0);
+    shouldBeEqualToNumber("entries[1].intersectionRect.top", 0);
+    shouldBeEqualToNumber("entries[1].intersectionRect.bottom", 0);
+    shouldBeEqualToNumber("entries[1].rootBounds.left", 11);
+    shouldBeEqualToNumber("entries[1].rootBounds.right", 111);
+    shouldBeEqualToNumber("entries[1].rootBounds.top", 711);
+    shouldBeEqualToNumber("entries[1].rootBounds.bottom", 911);
+    shouldEvaluateToSameObject("entries[1].target", target);
   }
+  root.scrollTop = 150;
+  requestAnimationFrame(step5);
+}
 
-  // This tests that notifications are generated even when the root element is off screen.
-  function step5() {
-    setTimeout(function() {
-      shouldBeEqualToNumber("entries.length", 3);
-      shouldBeEqualToNumber("entries[2].boundingClientRect.left", 11);
-      shouldBeEqualToNumber("entries[2].boundingClientRect.right", 111);
-      shouldBeEqualToNumber("entries[2].boundingClientRect.top", 861);
-      shouldBeEqualToNumber("entries[2].boundingClientRect.bottom", 961);
-      shouldBeEqualToNumber("entries[2].intersectionRect.left", 11);
-      shouldBeEqualToNumber("entries[2].intersectionRect.right", 111);
-      shouldBeEqualToNumber("entries[2].intersectionRect.top", 861);
-      shouldBeEqualToNumber("entries[2].intersectionRect.bottom", 911);
-      shouldBeEqualToNumber("entries[2].rootBounds.left", 11);
-      shouldBeEqualToNumber("entries[2].rootBounds.right", 111);
-      shouldBeEqualToNumber("entries[2].rootBounds.top", 711);
-      shouldBeEqualToNumber("entries[2].rootBounds.bottom", 911);
-      shouldEvaluateToSameObject("entries[2].target", target);
-      finishJSTest();
-    });
+// This tests that notifications are generated even when the root element is off screen.
+function step5() {
+  entries = entries.concat(observer.takeRecords());
+  shouldBeEqualToNumber("entries.length", 3);
+  if (entries.length > 2) {
+    shouldBeEqualToNumber("entries[2].boundingClientRect.left", 11);
+    shouldBeEqualToNumber("entries[2].boundingClientRect.right", 111);
+    shouldBeEqualToNumber("entries[2].boundingClientRect.top", 861);
+    shouldBeEqualToNumber("entries[2].boundingClientRect.bottom", 961);
+    shouldBeEqualToNumber("entries[2].intersectionRect.left", 11);
+    shouldBeEqualToNumber("entries[2].intersectionRect.right", 111);
+    shouldBeEqualToNumber("entries[2].intersectionRect.top", 861);
+    shouldBeEqualToNumber("entries[2].intersectionRect.bottom", 911);
+    shouldBeEqualToNumber("entries[2].rootBounds.left", 11);
+    shouldBeEqualToNumber("entries[2].rootBounds.right", 111);
+    shouldBeEqualToNumber("entries[2].rootBounds.top", 711);
+    shouldBeEqualToNumber("entries[2].rootBounds.bottom", 911);
+    shouldEvaluateToSameObject("entries[2].target", target);
   }
 
-  step0();
+  finishJSTest();
+}
 </script>