[IntersectionObserver] Apply overflow clip to document.scrollingElement

If the explicit root element is the document's scrollingElement, we interpret that to mean we should apply the root scroller's overflow clip (just as we already do with the implicit root). Hidden behind a flag for testing, and pending resolution of spec issues and sending intent's. BUG=1015183 R=chrishtr@chromium.org Change-Id: I6b2542dd353ea0be6b67b5922eee75445070f10a Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1865257 Commit-Queue: Stefan Zager <szager@chromium.org> Reviewed-by: Chris Harrelson <chrishtr@chromium.org> Cr-Commit-Position: refs/heads/master@{#706742}
web-platform-tests · Oct 17, 2019 · 796ebc4 · 796ebc4
1 parent bfd3e2a
commit 796ebc4
Showing 1 changed file with 52 additions and 0 deletions.
diff --git a/intersection-observer/document-scrolling-element-root.html b/intersection-observer/document-scrolling-element-root.html
@@ -0,0 +1,52 @@
+<!DOCTYPE html>
+<meta name="viewport" content="width=device-width,initial-scale=1">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="./resources/intersection-observer-test-utils.js"></script>
+
+<style>
+pre, #log {
+  position: absolute;
+  top: 0;
+  left: 200px;
+}
+iframe {
+  height: 250px;
+  width: 150px;
+  border: 0;
+}
+</style>
+<iframe id="target-iframe" src="resources/iframe-no-root-subframe.html"></iframe>
+
+<script>
+var iframe = document.getElementById("target-iframe");
+var target;
+var root;
+var entries = [];
+
+iframe.onload = function() {
+  runTestCycle(function() {
+    assert_true(!!iframe, "iframe exists");
+
+    root = iframe.contentDocument.scrollingElement;
+    assert_true(!!root, "Root element exists.");
+    target = iframe.contentDocument.getElementById("target");
+    assert_true(!!target, "Target element exists.");
+    var observer = new IntersectionObserver(function(changes) {
+      entries = entries.concat(changes)
+    }, { root: root });
+    observer.observe(target);
+    entries = entries.concat(observer.takeRecords());
+    assert_equals(entries.length, 0, "No initial notifications.");
+    runTestCycle(step0, "First rAF.");
+  }, "Observer with explicit root which is the document's scrolling element.");
+};
+
+function step0() {
+  let vw = iframe.contentDocument.documentElement.clientWidth;
+  let vh = iframe.contentDocument.documentElement.clientHeight;
+  // The target element is partially clipped by the iframe's root scroller, so
+  // height of the intersection rect is (250 - 208) == 42.
+  checkLastEntry(entries, 0, [8, 108, 208, 308, 8, 108, 208, 250, 0, vw, 0, vh, true]);
+}
+</script>