script: Support shadowrootslotassignment on template elements (#44246)

This brings up to date with the specification for declarative shadow
roots: https://github.com/whatwg/html/pull/12267.

The `shadowrootslotassignment` attribute on `<template>` elements
specifies the slot assignment mode used by the declarative shadow root
created by the template.

Testing: New tests start to pass

---------

Signed-off-by: Simon Wülker <simon.wuelker@arcor.de>

Cargo.lock

@@ -8800,6 +8800,7 @@ dependencies = [
  "url",
  "urlpattern",
  "uuid",
+ "web_atoms",
  "webdriver",
  "webrender_api",
  "wgpu-core",
@@ -11028,9 +11029,9 @@ dependencies = [
 
 [[package]]
 name = "web_atoms"
-version = "0.2.3"
+version = "0.2.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "57a9779e9f04d2ac1ce317aee707aa2f6b773afba7b931222bff6983843b1576"
+checksum = "d7cff6eef815df1834fd250e3a2ff436044d82a9f1bc1980ca1dbdf07effc538"
 dependencies = [
  "phf",
  "phf_codegen",

Cargo.toml

@@ -363,7 +363,7 @@ codegen-units = 1
 # web_atoms = { path = "../html5ever/web_atoms" }
 # xml5ever = { path = "../html5ever/xml5ever" }
 # tendril = { path = "../html5ever/tendril" }
-
+#
 # For WebRender:
 #
 # webrender = { path = "../webrender/webrender" }

components/script/Cargo.toml

@@ -164,6 +164,7 @@ unicode-script = { workspace = true }
 url = { workspace = true }
 urlpattern = { workspace = true }
 uuid = { workspace = true, features = ["serde"] }
+web_atoms = "0.2.4"
 webdriver = { workspace = true }
 webgpu_traits = { workspace = true, optional = true }
 webrender_api = { workspace = true }

components/script/dom/html/htmltemplateelement.rs

@@ -85,6 +85,18 @@ impl HTMLTemplateElementMethods<crate::DomTypeHolder> for HTMLTemplateElement {
     /// <https://html.spec.whatwg.org/multipage/#dom-template-shadowrootdelegatesfocus>
     make_bool_setter!(SetShadowRootDelegatesFocus, "shadowrootdelegatesfocus");
 
+    /// <https://html.spec.whatwg.org/multipage/#attr-template-shadowrootslotassignment>
+    make_enumerated_getter!(
+        ShadowRootSlotAssignment,
+        "shadowrootslotassignment",
+        "named" | "manual",
+        missing => "named",
+        invalid => "named"
+    );
+
+    /// <https://html.spec.whatwg.org/multipage/#attr-template-shadowrootslotassignment>
+    make_atomic_setter!(SetShadowRootSlotAssignment, "shadowrootslotassignment");
+
     /// <https://html.spec.whatwg.org/multipage/#dom-template-shadowrootclonable>
     make_bool_getter!(ShadowRootClonable, "shadowrootclonable");
 

components/script/dom/servoparser/mod.rs

@@ -2109,34 +2109,28 @@ fn attach_declarative_shadow_inner(
 
     let template_element = template.downcast::<HTMLTemplateElement>().unwrap();
 
-    // Step 3. Let mode be template start tag's shadowrootmode attribute's value.
-    // Step 4. Let clonable be true if template start tag has a shadowrootclonable attribute; otherwise false.
-    // Step 5. Let delegatesfocus be true if template start tag
-    // has a shadowrootdelegatesfocus attribute; otherwise false.
-    // Step 6. Let serializable be true if template start tag
-    // has a shadowrootserializable attribute; otherwise false.
+    // Step 3. Let mode be templateStartTag's shadowrootmode attribute's value.
+    // Step 4. Let slotAssignment be "named".
+    // Step 5. If templateStartTag's shadowrootslotassignment attribute is in
+    // the Manual state, then set slotAssignment to "manual".
+    // Step 6. Let clonable be true if templateStartTag has a shadowrootclonable attribute; otherwise false.
+    // Step 7. Let serializable be true if templateStartTag has a shadowrootserializable
+    // attribute; otherwise false.
+    // Step 8. Let delegatesFocus be true if templateStartTag has a shadowrootdelegatesfocus
+    // attribute; otherwise false.
     let mut shadow_root_mode = ShadowRootMode::Open;
+    let mut slot_assignment_mode = SlotAssignmentMode::Named;
     let mut clonable = false;
     let mut delegatesfocus = false;
     let mut serializable = false;
 
-    let attributes: Vec<ElementAttribute> = attributes
-        .iter()
-        .map(|attr| {
-            ElementAttribute::new(
-                attr.name.clone(),
-                DOMString::from(String::from(attr.value.clone())),
-            )
-        })
-        .collect();
-
     attributes
         .iter()
-        .for_each(|attr: &ElementAttribute| match attr.name.local {
+        .for_each(|attr: &Attribute| match attr.name.local {
             local_name!("shadowrootmode") => {
-                if attr.value.str().eq_ignore_ascii_case("open") {
+                if attr.value.eq_ignore_ascii_case("open") {
                     shadow_root_mode = ShadowRootMode::Open;
-                } else if attr.value.str().eq_ignore_ascii_case("closed") {
+                } else if attr.value.eq_ignore_ascii_case("closed") {
                     shadow_root_mode = ShadowRootMode::Closed;
                 } else {
                     unreachable!("shadowrootmode value is not open nor closed");
@@ -2151,6 +2145,11 @@ fn attach_declarative_shadow_inner(
             local_name!("shadowrootserializable") => {
                 serializable = true;
             },
+            local_name!("shadowrootslotassignment") => {
+                if attr.value.eq_ignore_ascii_case("manual") {
+                    slot_assignment_mode = SlotAssignmentMode::Manual;
+                }
+            },
             _ => {},
         });
 
@@ -2163,7 +2162,7 @@ fn attach_declarative_shadow_inner(
         clonable,
         serializable,
         delegatesfocus,
-        SlotAssignmentMode::Named,
+        slot_assignment_mode,
     ) {
         Ok(shadow_root) => {
             // Step 8.3. Set shadow's declarative to true.

components/script_bindings/webidls/HTMLTemplateElement.webidl

@@ -10,6 +10,7 @@ interface HTMLTemplateElement : HTMLElement {
   readonly attribute DocumentFragment content;
   [CEReactions] attribute DOMString shadowRootMode;
   [CEReactions] attribute boolean shadowRootDelegatesFocus;
+  [CEReactions] attribute DOMString shadowRootSlotAssignment;
   [CEReactions] attribute boolean shadowRootClonable;
   [CEReactions] attribute boolean shadowRootSerializable;
 };

tests/wpt/meta/shadow-dom/declarative/declarative-shadow-dom-repeats-slot-assignment.html.ini

@@ -1,6 +0,0 @@
-[declarative-shadow-dom-repeats-slot-assignment.html]
-  [attachShadow() on declarative shadow root with manual slotAssignment]
-    expected: FAIL
-
-  [attachShadow() on declarative shadow root does not change slotAssignment]
-    expected: FAIL

tests/wpt/meta/shadow-dom/declarative/declarative-shadow-dom-slot-assignment.html.ini

@@ -1,15 +0,0 @@
-[declarative-shadow-dom-slot-assignment.html]
-  [shadowrootslotassignment reflection]
-    expected: FAIL
-
-  [shadowrootslotassignment reflection, setter]
-    expected: FAIL
-
-  [Declarative Shadow DOM: shadowrootslotassignment=manual]
-    expected: FAIL
-
-  [Declarative Shadow DOM: shadowrootslotassignment is case insensitive]
-    expected: FAIL
-
-  [Declarative Shadow DOM: shadowrootslotassignment on closed shadows can be set to manual]
-    expected: FAIL