[@container] Traverse shadow-including ancestors for container units

Fixed: 1325047 Change-Id: I69c381111b9d89f71fbb575cfcc25b58e12a546f
web-platform-tests · May 13, 2022 · b7375f3 · b7375f3
1 parent c95ef3b
commit b7375f3
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Showing 3 changed files with 75 additions and 11 deletions.
diff --git a/css/css-contain/container-queries/container-for-shadow-dom.html b/css/css-contain/container-queries/container-for-shadow-dom.html
@@ -230,17 +230,7 @@
 <script>
   setup(() => {
     assert_implements_container_queries();
-
-    // Fallback for browsers not supporting declarative Shadow DOM
-    (function attachShadowRoots(root) {
-      root.querySelectorAll("template[shadowroot]").forEach(template => {
-        const mode = template.getAttribute("shadowroot");
-        const shadowRoot = template.parentNode.attachShadow({ mode });
-        shadowRoot.appendChild(template.content);
-        template.remove();
-        attachShadowRoots(shadowRoot);
-      });
-    })(document);
+    polyfill_declarative_shadow_dom(document);
   });
 
   const green = "rgb(0, 128, 0)";

diff --git a/css/css-contain/container-queries/container-units-shadow.html b/css/css-contain/container-queries/container-units-shadow.html
@@ -0,0 +1,64 @@
+<!doctype html>
+<title>Container Relative Units: Shadow DOM</title>
+<link rel="help" href="https://drafts.csswg.org/css-contain-3/#container-lengths">
+<link rel="help" href="https://drafts.csswg.org/css-contain-3/#container-queries">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="support/cq-testcommon.js"></script>
+<style>
+  #outer {
+    container-type: size;
+    width: 200px;
+    height: 200px;
+  }
+  #direct {
+    container-type: inline-size;
+    width: 50cqw;
+    height: 50cqh;
+  }
+  #nondirect {
+    width: 10cqw;
+    height: 10cqh;
+    background: green;
+  }
+</style>
+<div id=outer>
+  <div>
+    <template shadowroot="open">
+      <style>
+        #inner {
+          container-type: size;
+          width: 30px;
+          height: 30px;
+        }
+      </style>
+      <div id=inner>
+        <slot></slot>
+      </div>
+    </template>
+    <div>
+      <div id=direct>
+        <div id=nondirect>
+        </div>
+      </div>
+    </div>
+  </div>
+</div>
+<script>
+  setup(() => {
+    assert_implements_container_queries();
+    polyfill_declarative_shadow_dom(document);
+  });
+
+  test(() => {
+    let cs = getComputedStyle(direct);
+    assert_equals(cs.width, '100px');
+    assert_equals(cs.height, '100px');
+  }, 'Direct slotted child queries shadow-including ancestors');
+
+  test(() => {
+    let cs = getComputedStyle(nondirect);
+    assert_equals(cs.width, '10px'); // #direct
+    assert_equals(cs.height, '20px'); // #outer
+  }, 'Nondirect slotted child queries shadow-including ancestors');
+</script>
diff --git a/css/css-contain/container-queries/support/cq-testcommon.js b/css/css-contain/container-queries/support/cq-testcommon.js
@@ -1,3 +1,13 @@
 function assert_implements_container_queries() {
   assert_implements(CSS.supports("container-type:size"), "Basic support for container queries required");
 }
+
+function polyfill_declarative_shadow_dom(root) {
+  root.querySelectorAll("template[shadowroot]").forEach(template => {
+    const mode = template.getAttribute("shadowroot");
+    const shadowRoot = template.parentNode.attachShadow({ mode });
+    shadowRoot.appendChild(template.content);
+    template.remove();
+    polyfill_declarative_shadow_dom(shadowRoot);
+  });
+}