[anchor-position] Update layout on anchor attribute changes

This patch also adds WPTs for the anchor attribute (without popovers) to support the HTML PR whatwg/html#9144 Fixed: 1432016 Change-Id: I3e80326268008e6beaf74389bb32c01050406a81 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4434155 Commit-Queue: Joey Arhar <[email protected]> Commit-Queue: Xiaocheng Hu <[email protected]> Reviewed-by: Joey Arhar <[email protected]> Code-Coverage: Findit <[email protected]> Auto-Submit: Xiaocheng Hu <[email protected]> Cr-Commit-Position: refs/heads/main@{#1131479}
web-platform-tests · Apr 17, 2023 · db5d950 · db5d950
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diff --git a/html/dom/elements/global-attributes/the-anchor-attribute-001.tentative.html b/html/dom/elements/global-attributes/the-anchor-attribute-001.tentative.html
@@ -0,0 +1,39 @@
+<!DOCTYPE html>
+<link rel="help" href="https://github.com/whatwg/html/pull/9144">
+<link rel="author" href="mailto:[email protected]">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<style>
+body {
+  margin: 0;
+}
+#anchor {
+  width: 100px;
+  height: 100px;
+  margin-left: 50px;
+  margin-top: 50px;
+  background: orange;
+}
+#target {
+  position: absolute;
+  left: anchor(right);
+  top: anchor(top);
+  width: 100px;
+  height: 100px;
+  background: lime;
+}
+</style>
+<div id="anchor"></div>
+<div id="target" anchor="anchor"></div>
+
+<script>
+test(() => {
+  assert_equals(target.offsetLeft, 150);
+  assert_equals(target.offsetTop, 50);
+}, 'The anchor attribute should position the target element next to its implicit anchor');
+
+test(() => {
+  assert_equals(target.anchorElement, anchor);
+}, 'The element.anchorElement IDL should reflect the element pointed to by the anchor attribute');
+</script>
diff --git a/html/dom/elements/global-attributes/the-anchor-attribute-002.tentative.html b/html/dom/elements/global-attributes/the-anchor-attribute-002.tentative.html
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+<!DOCTYPE html>
+<link rel="help" href="https://github.com/whatwg/html/pull/9144">
+<link rel="author" href="mailto:[email protected]">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<style>
+body {
+  margin: 0;
+}
+.anchor {
+  width: 100px;
+  height: 100px;
+  margin-left: 50px;
+  margin-top: 50px;
+  background: orange;
+}
+.target {
+  position: absolute;
+  left: anchor(right, 123px);
+  top: anchor(top, 456px);
+  width: 100px;
+  height: 100px;
+  background: lime;
+}
+</style>
+<div class="anchor" id="anchor1"></div>
+<div class="anchor" id="anchor2"></div>
+<div class="target" id="target1" anchor="anchor1"></div>
+<div class="target" id="target2" anchor="anchor1"></div>
+
+<script>
+test(() => {
+  document.body.offsetLeft; // Force layout
+  target1.setAttribute('anchor', 'anchor2');
+  assert_equals(target1.offsetLeft, 150);
+  assert_equals(target1.offsetTop, 200);
+
+  target1.setAttribute('anchor', 'anchor1');
+  assert_equals(target1.offsetLeft, 150);
+  assert_equals(target1.offsetTop, 50);
+}, 'Layout should be updated when anchor attribute changes to another element');
+
+test(() => {
+  document.body.offsetLeft; // Force layout
+  target2.setAttribute('anchor', 'nonexist-anchor');
+  assert_equals(target2.offsetLeft, 123);
+  assert_equals(target2.offsetTop, 456);
+}, 'Layout should be updated when anchor attribute changes to a non-existent element');
+</script>