::backdrop is tree-abiding and should be allowed after ::slotted()

https://bugs.webkit.org/show_bug.cgi?id=265611 Reviewed by Tim Nguyen. This patch is to align WebKIt with Blink / Chromium and Web-Specification [1]: Merge: https://chromium-review.googlesource.com/c/chromium/src/+/4778566 [1] https://drafts.csswg.org/css-position-4/#backdrop When ::backdrop was moved into css-position, it was made tree-abiding, which means that '::slotted()::backdrop' should be allowed. This PR also syncs WPT test from upstream: Upstream Hash: web-platform-tests/wpt@3e2d8fc * Source/WebCore/css/parser/CSSSelectorParser.cpp: (isTreeAbidingPseudoElement): * LayoutTests/imported/w3c/web-platform-tests/css/css-position/w3c-import.log: * LayoutTests/imported/w3c/web-platform-tests/css/css-position/backdrop-tree-abiding-slotted.html: Add Test Case * LayoutTests/imported/w3c/web-platform-tests/css/css-position/backdrop-tree-abiding-slotted-expected.txt: Add Test Case Expectation Canonical link: https://commits.webkit.org/271366@main
WebKit · Dec 1, 2023 · 01864fd · 01864fd
1 parent 9ab66ea
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diff --git a/...ported/w3c/web-platform-tests/css/css-position/backdrop-tree-abiding-slotted-expected.txt b/...ported/w3c/web-platform-tests/css/css-position/backdrop-tree-abiding-slotted-expected.txt
@@ -0,0 +1,3 @@
+
+PASS ::backdrop is tree-abiding and should be allowed after ::slotted()
+
diff --git a/...Tests/imported/w3c/web-platform-tests/css/css-position/backdrop-tree-abiding-slotted.html b/...Tests/imported/w3c/web-platform-tests/css/css-position/backdrop-tree-abiding-slotted.html
@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Position Test: ::backdrop is tree abiding, allowed after ::slotted</title>
+<link rel="help" href="https://drafts.csswg.org/css-position-4/#backdrop">
+<link rel="help" href="https://drafts.csswg.org/css-pseudo-4/#tree-abiding">
+<link rel="help" href="https://drafts.csswg.org/css-scoping/#slotted-pseudo">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/declarative-shadow-dom-polyfill.js"></script>
+<div>
+  <template shadowrootmode="open">
+    <style>
+      ::slotted(dialog)::backdrop {
+        background-color: green;
+      }
+    </style>
+    <slot></slot>
+  </template>
+  <dialog id="target"></dialog>
+</div>
+<script>
+  const target = document.getElementById("target");
+  target.showModal();
+
+  test(() => {
+    assert_equals(getComputedStyle(target, "::backdrop").backgroundColor, "rgb(0, 128, 0)");
+  }, "::backdrop is tree-abiding and should be allowed after ::slotted()");
+</script>
diff --git a/LayoutTests/imported/w3c/web-platform-tests/css/css-position/w3c-import.log b/LayoutTests/imported/w3c/web-platform-tests/css/css-position/w3c-import.log
@@ -15,6 +15,7 @@ None
 ------------------------------------------------------------------------
 List of files:
 /LayoutTests/imported/w3c/web-platform-tests/css/css-position/META.yml
+/LayoutTests/imported/w3c/web-platform-tests/css/css-position/backdrop-tree-abiding-slotted.html
 /LayoutTests/imported/w3c/web-platform-tests/css/css-position/fixed-z-index-blend-expected.html
 /LayoutTests/imported/w3c/web-platform-tests/css/css-position/fixed-z-index-blend.html
 /LayoutTests/imported/w3c/web-platform-tests/css/css-position/hypothetical-box-scroll-parent-expected.html

diff --git a/Source/WebCore/css/parser/CSSSelectorParser.cpp b/Source/WebCore/css/parser/CSSSelectorParser.cpp
@@ -466,6 +466,7 @@ static bool isTreeAbidingPseudoElement(CSSSelector::PseudoElementType pseudoElem
     case CSSSelector::PseudoElementBefore:
     case CSSSelector::PseudoElementAfter:
     case CSSSelector::PseudoElementMarker:
+    case CSSSelector::PseudoElementBackdrop:
         return true;
     default:
         return false;