optimize createElement for divs

Author: mukilan

components/script/dom/bindings/constructor.rs

@@ -183,6 +183,7 @@ fn html_constructor(
                     &document,
                     ElementCreator::ScriptCreated,
                     None,
+                    false
                 )
             };
 

components/script/dom/create.rs

@@ -151,7 +151,7 @@ fn create_html_element(
             // local name set to localName, custom element state set to "undefined",
             // custom element definition set to null, is value set to is,
             // and node document set to document.
-            let element = create_native_html_element(name, prefix, document, creator, proto);
+            let element = create_native_html_element(name, prefix, document, creator, proto, false);
             element.set_is(definition.name.clone());
             element.set_custom_element_state(CustomElementState::Undefined);
             match mode {
@@ -236,7 +236,8 @@ fn create_html_element(
     // namespace set to namespace, namespace prefix set to prefix, local name set to localName,
     // custom element state set to "uncustomized", custom element definition set to null,
     // is value set to is, and node document set to document.
-    let result = create_native_html_element(name.clone(), prefix, document, creator, proto);
+    let is_builtin = is.is_none() && !is_valid_custom_element_name(&name.local);
+    let result = create_native_html_element(name.clone(), prefix, document, creator, proto, is_builtin);
     // Step 5.3. If namespace is the HTML namespace, and either localName is a valid custom element name or
     // is is non-null, then set result’s custom element state to "undefined".
     match is {
@@ -247,8 +248,6 @@ fn create_html_element(
         None => {
             if is_valid_custom_element_name(&name.local) {
                 result.set_custom_element_state(CustomElementState::Undefined);
-            } else {
-                result.set_custom_element_state(CustomElementState::Uncustomized);
             }
         },
     };
@@ -263,6 +262,7 @@ pub(crate) fn create_native_html_element(
     document: &Document,
     creator: ElementCreator,
     proto: Option<HandleObject>,
+    defined: bool,
 ) -> DomRoot<Element> {
     assert_eq!(name.ns, ns!(html));
 
@@ -318,7 +318,14 @@ pub(crate) fn create_native_html_element(
         local_name!("dfn") => make!(HTMLElement),
         local_name!("dialog") => make!(HTMLDialogElement),
         local_name!("dir") => make!(HTMLDirectoryElement),
-        local_name!("div") => make!(HTMLDivElement),
+        local_name!("div") => {
+            let obj = if defined {
+                HTMLDivElement::new_defined(name.local, prefix, document, proto, CanGc::note())
+            } else {
+                HTMLDivElement::new(name.local, prefix, document, proto, CanGc::note())
+            };
+            DomRoot::upcast(obj)
+        },
         local_name!("dl") => make!(HTMLDListElement),
         local_name!("dt") => make!(HTMLElement),
         local_name!("em") => make!(HTMLElement),

components/script/dom/customelementregistry.rs

@@ -50,7 +50,7 @@ use crate::script_runtime::{CanGc, JSContext};
 use crate::script_thread::ScriptThread;
 
 /// <https://dom.spec.whatwg.org/#concept-element-custom-element-state>
-#[derive(Clone, Copy, Default, Eq, JSTraceable, MallocSizeOf, PartialEq)]
+#[derive(Clone, Copy, Debug, Default, Eq, JSTraceable, MallocSizeOf, PartialEq)]
 pub(crate) enum CustomElementState {
     Undefined,
     Failed,

components/script/dom/htmldivelement.rs

@@ -5,6 +5,7 @@
 use dom_struct::dom_struct;
 use html5ever::{LocalName, Prefix};
 use js::rust::HandleObject;
+use stylo_dom::ElementState;
 
 use crate::dom::bindings::codegen::Bindings::HTMLDivElementBinding::HTMLDivElementMethods;
 use crate::dom::bindings::root::DomRoot;
@@ -30,6 +31,29 @@ impl HTMLDivElement {
         }
     }
 
+    #[cfg_attr(crown, allow(crown::unrooted_must_root))]
+    pub(crate) fn new_defined(
+        local_name: LocalName,
+        prefix: Option<Prefix>,
+        document: &Document,
+        proto: Option<HandleObject>,
+        can_gc: CanGc,
+    ) -> DomRoot<HTMLDivElement> {
+        Node::reflect_node_with_proto(
+            Box::new(HTMLDivElement {
+                htmlelement: HTMLElement::new_inherited_with_state(
+                    ElementState::DEFINED,
+                    local_name,
+                    prefix,
+                    document
+                )
+            }),
+            document,
+            proto,
+            can_gc,
+        )
+    }
+
     #[cfg_attr(crown, allow(crown::unrooted_must_root))]
     pub(crate) fn new(
         local_name: LocalName,