script: Move code generation and webidl files to new script_bindings crate. (#35157)

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

components/script_bindings/webidls/CustomElementRegistry.webidl

@@ -0,0 +1,28 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+// https://html.spec.whatwg.org/multipage/#customelementregistry
+[Exposed=Window, Pref="dom_customelements_enabled"]
+interface CustomElementRegistry {
+  [Throws, CEReactions]
+  undefined define(
+    DOMString name,
+    CustomElementConstructor constructor_,
+    optional ElementDefinitionOptions options = {}
+  );
+
+  any get(DOMString name);
+
+  DOMString? getName(CustomElementConstructor constructor);
+
+  Promise<CustomElementConstructor> whenDefined(DOMString name);
+
+  [CEReactions] undefined upgrade(Node root);
+};
+
+callback CustomElementConstructor = HTMLElement();
+
+dictionary ElementDefinitionOptions {
+  DOMString extends;
+};