Add a way not to sanitize values in an input until its creation is done

components/script/dom/bindings/htmlconstructor.rs

@@ -166,6 +166,8 @@ where
             // Step 8.4
             element.set_custom_element_definition(definition.clone());
 
+            element.done_creating();
+
             // Step 8.5
             DomRoot::downcast(element).ok_or(Error::InvalidState)
         },

components/script/dom/element.rs

@@ -14,6 +14,7 @@ use dom::bindings::codegen::Bindings::ElementBinding;
 use dom::bindings::codegen::Bindings::ElementBinding::ElementMethods;
 use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
 use dom::bindings::codegen::Bindings::FunctionBinding::Function;
+use dom::bindings::codegen::Bindings::HTMLInputElementBinding::HTMLInputElementBinding::HTMLInputElementMethods;
 use dom::bindings::codegen::Bindings::HTMLTemplateElementBinding::HTMLTemplateElementMethods;
 use dom::bindings::codegen::Bindings::NodeBinding::NodeMethods;
 use dom::bindings::codegen::Bindings::WindowBinding::{ScrollBehavior, ScrollToOptions};
@@ -159,6 +160,7 @@ pub struct Element {
     custom_element_definition: DomRefCell<Option<Rc<CustomElementDefinition>>>,
     /// <https://dom.spec.whatwg.org/#concept-element-custom-element-state>
     custom_element_state: Cell<CustomElementState>,
+    done_creating: Cell<bool>,
 }
 
 impl fmt::Debug for Element {
@@ -243,6 +245,18 @@ impl Element {
         document: &Document,
         creator: ElementCreator,
         mode: CustomElementCreationMode,
+    ) -> DomRoot<Element> {
+        let el = Element::create_unfinished(name, is, document, creator, mode);
+        el.done_creating();
+        el
+    }
+
+    pub fn create_unfinished(
+        name: QualName,
+        is: Option<LocalName>,
+        document: &Document,
+        creator: ElementCreator,
+        mode: CustomElementCreationMode,
     ) -> DomRoot<Element> {
         create_element(name, is, document, creator, mode)
     }
@@ -286,9 +300,21 @@ impl Element {
             custom_element_reaction_queue: Default::default(),
             custom_element_definition: Default::default(),
             custom_element_state: Cell::new(CustomElementState::Uncustomized),
+            done_creating: Cell::new(false),
+        }
+    }
+
+    pub fn done_creating(&self) {
+        self.done_creating.set(true);
+        if let Some(el) = self.downcast::<HTMLInputElement>() {
+            el.refresh_value(el.Value());
         }
     }
 
+    pub fn is_done_creating(&self) -> bool {
+        self.done_creating.get()
+    }
+
     pub fn new(
         local_name: LocalName,
         namespace: Namespace,

components/script/dom/htmlinputelement.rs

@@ -1122,8 +1122,18 @@ impl HTMLInputElement {
         }
     }
 
+    pub fn refresh_value(&self, mut value: DOMString) {
+        let mut textinput = self.textinput.borrow_mut();
+        self.sanitize_value(&mut value);
+        textinput.set_content(value);
+    }
+
     // https://html.spec.whatwg.org/multipage/#value-sanitization-algorithm
     fn sanitize_value(&self, value: &mut DOMString) {
+        let el = self.upcast::<Element>();
+        if !el.is_done_creating() {
+            return
+        }
         match self.input_type() {
             InputType::Text | InputType::Search | InputType::Tel | InputType::Password => {
                 value.strip_newlines();

components/script/dom/servoparser/mod.rs

@@ -1120,13 +1120,15 @@ fn create_element_for_token(
     } else {
         CustomElementCreationMode::Asynchronous
     };
-    let element = Element::create(name, is, document, creator, creation_mode);
+    let element = Element::create_unfinished(name, is, document, creator, creation_mode);
 
     // Step 8.
     for attr in attrs {
         element.set_attribute_from_parser(attr.name, attr.value, None);
     }
 
+    element.done_creating();
+
     // Step 9.
     if will_execute_script {
         // Steps 9.1 - 9.2.