Implement updated HTML language inheritance rules.
This makes two changes to match the HTML spec:
* only honor the unnamespaced lang attribute on HTML and SVG elements
* have <slot> elements in a shadow tree inherit language from the shadow
host
Note that an update to the HTML specification regarding the SVG elements
case is proposed in https://github.com/whatwg/html/pull/9882, but
https://www.w3.org/TR/SVG/struct.html#LangAttribute already defines it.
These changes match the related changes to the dir attribute, but use a
separate feature flag as a killswitch, since they are separable.
Fixed: 1490711
Bug: 576815
Change-Id: I6462181e6d4433aa1dcc9a2c42e5c12754830e52
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4974775
Commit-Queue: Di Zhang <dizhangg@chromium.org>
Commit-Queue: David Baron <dbaron@chromium.org>
Reviewed-by: Di Zhang <dizhangg@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1215017}
diff --git a/html/dom/elements/global-attributes/lang-attribute.window.js b/html/dom/elements/global-attributes/lang-attribute.window.js
new file mode 100644
index 0000000..de0c03e
--- /dev/null
+++ b/html/dom/elements/global-attributes/lang-attribute.window.js
@@ -0,0 +1,16 @@
+test(() => {
+ const container = document.createElement("div");
+ document.body.append(container);
+ container.setAttribute("lang", "en-CA");
+
+ const child = document.createElementNS("div", "test");
+ container.append(child);
+ child.setAttribute("lang", "en-NZ");
+
+ assert_true(container.matches(":lang(en-CA)"), "container matches en-CA");
+ assert_true(child.matches(":lang(en-CA)"), "child matches en-CA");
+ assert_false(container.matches(":lang(en-NZ)"), "container does not match en-NZ");
+ assert_false(child.matches(":lang(en-NZ)"), "child does not match en-NZ");
+
+ container.remove();
+}, "unnamespaced lang attribute only works on elements in the HTML namespace");
