css: Refactor StyleSheetInDocument owner (#38136)

Refactor `documentotshadowroot::StyleSheetInDocument`, renaming it into
`ServoStylesheetInDocument` to avoid confusion with Stylo's
`StylesheetInDocument` trait.

To support constructed stylesheet. The `ServoStylesheetInDocument.owner`
would contains enum of:
- `Dom<Element>` - for stylesheet parsed from an element.
- `Dom<CSSStylesheet>` - for constructed stylesheet.

Testing: No WPT regression.
Fixes: #38133

---------

Signed-off-by: Jo Steven Novaryo <jo.steven.novaryo@huawei.com>

components/script/dom/documentorshadowroot.rs

@@ -26,46 +26,77 @@ use crate::dom::element::Element;
 use crate::dom::htmlelement::HTMLElement;
 use crate::dom::node::{self, Node, VecPreOrderInsertionHelper};
 use crate::dom::shadowroot::ShadowRoot;
+use crate::dom::types::CSSStyleSheet;
 use crate::dom::window::Window;
 use crate::script_runtime::CanGc;
 use crate::stylesheet_set::StylesheetSetRef;
 
+/// Stylesheet could be constructed by a CSSOM object CSSStylesheet or parsed
+/// from HTML element such as `<style>` or `<link>`.
 #[derive(Clone, JSTraceable, MallocSizeOf)]
 #[cfg_attr(crown, crown::unrooted_must_root_lint::must_root)]
-pub(crate) struct StyleSheetInDocument {
+pub(crate) enum StylesheetSource {
+    Element(Dom<Element>),
+    // TODO(stevennovaryo): This type of enum would not be used until we implement adopted stylesheet
+    #[allow(dead_code)]
+    Constructed(Dom<CSSStyleSheet>),
+}
+
+impl StylesheetSource {
+    pub(crate) fn get_cssom_object(&self) -> Option<DomRoot<CSSStyleSheet>> {
+        match self {
+            StylesheetSource::Element(el) => el.upcast::<Node>().get_cssom_stylesheet(),
+            StylesheetSource::Constructed(ss) => Some(ss.as_rooted()),
+        }
+    }
+
+    pub(crate) fn is_a_valid_owner(&self) -> bool {
+        match self {
+            StylesheetSource::Element(el) => el.as_stylesheet_owner().is_some(),
+            StylesheetSource::Constructed(ss) => ss.is_constructed(),
+        }
+    }
+}
+
+#[derive(Clone, JSTraceable, MallocSizeOf)]
+#[cfg_attr(crown, crown::unrooted_must_root_lint::must_root)]
+pub(crate) struct ServoStylesheetInDocument {
     #[ignore_malloc_size_of = "Arc"]
     #[no_trace]
     pub(crate) sheet: Arc<Stylesheet>,
-    pub(crate) owner: Dom<Element>,
+    /// The object that owns this stylesheet. For constructed stylesheet, it would be the
+    /// CSSOM object itself, and for stylesheet generated by an element, it would be the
+    /// html element. This is used to get the CSSOM Stylesheet within a DocumentOrShadowDOM.
+    pub(crate) owner: StylesheetSource,
 }
 
 // This is necessary because this type is contained within a Stylo type which needs
 // Stylo's version of MallocSizeOf.
-impl stylo_malloc_size_of::MallocSizeOf for StyleSheetInDocument {
+impl stylo_malloc_size_of::MallocSizeOf for ServoStylesheetInDocument {
     fn size_of(&self, ops: &mut stylo_malloc_size_of::MallocSizeOfOps) -> usize {
-        <StyleSheetInDocument as malloc_size_of::MallocSizeOf>::size_of(self, ops)
+        <ServoStylesheetInDocument as malloc_size_of::MallocSizeOf>::size_of(self, ops)
     }
 }
 
-impl fmt::Debug for StyleSheetInDocument {
+impl fmt::Debug for ServoStylesheetInDocument {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
         self.sheet.fmt(formatter)
     }
 }
 
-impl PartialEq for StyleSheetInDocument {
+impl PartialEq for ServoStylesheetInDocument {
     fn eq(&self, other: &Self) -> bool {
         Arc::ptr_eq(&self.sheet, &other.sheet)
     }
 }
 
-impl ToMediaListKey for StyleSheetInDocument {
+impl ToMediaListKey for ServoStylesheetInDocument {
     fn to_media_list_key(&self) -> MediaListKey {
         self.sheet.contents.to_media_list_key()
     }
 }
 
-impl ::style::stylesheets::StylesheetInDocument for StyleSheetInDocument {
+impl ::style::stylesheets::StylesheetInDocument for ServoStylesheetInDocument {
     fn enabled(&self) -> bool {
         self.sheet.enabled()
     }
@@ -85,7 +116,7 @@ impl ::style::stylesheets::StylesheetInDocument for StyleSheetInDocument {
 
 // https://w3c.github.io/webcomponents/spec/shadow/#extensions-to-the-documentorshadowroot-mixin
 #[cfg_attr(crown, crown::unrooted_must_root_lint::must_root)]
-#[derive(JSTraceable, MallocSizeOf)]
+#[derive(Clone, JSTraceable, MallocSizeOf)]
 pub(crate) struct DocumentOrShadowRoot {
     window: Dom<Window>,
 }
@@ -225,18 +256,18 @@ impl DocumentOrShadowRoot {
     /// Remove a stylesheet owned by `owner` from the list of document sheets.
     #[cfg_attr(crown, allow(crown::unrooted_must_root))] // Owner needs to be rooted already necessarily.
     pub(crate) fn remove_stylesheet(
-        owner: &Element,
+        owner: StylesheetSource,
         s: &Arc<Stylesheet>,
-        mut stylesheets: StylesheetSetRef<StyleSheetInDocument>,
+        mut stylesheets: StylesheetSetRef<ServoStylesheetInDocument>,
     ) {
         let guard = s.shared_lock.read();
 
         // FIXME(emilio): Would be nice to remove the clone, etc.
         stylesheets.remove_stylesheet(
             None,
-            StyleSheetInDocument {
+            ServoStylesheetInDocument {
                 sheet: s.clone(),
-                owner: Dom::from_ref(owner),
+                owner,
             },
             &guard,
         );
@@ -246,18 +277,15 @@ impl DocumentOrShadowRoot {
     /// correct tree position.
     #[cfg_attr(crown, allow(crown::unrooted_must_root))] // Owner needs to be rooted already necessarily.
     pub(crate) fn add_stylesheet(
-        owner: &Element,
-        mut stylesheets: StylesheetSetRef<StyleSheetInDocument>,
+        owner: StylesheetSource,
+        mut stylesheets: StylesheetSetRef<ServoStylesheetInDocument>,
         sheet: Arc<Stylesheet>,
-        insertion_point: Option<StyleSheetInDocument>,
+        insertion_point: Option<ServoStylesheetInDocument>,
         style_shared_lock: &StyleSharedRwLock,
     ) {
-        debug_assert!(owner.as_stylesheet_owner().is_some(), "Wat");
+        debug_assert!(owner.is_a_valid_owner(), "Wat");
 
-        let sheet = StyleSheetInDocument {
-            sheet,
-            owner: Dom::from_ref(owner),
-        };
+        let sheet = ServoStylesheetInDocument { sheet, owner };
 
         let guard = style_shared_lock.read();