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/MessagePort.webidl

@@ -0,0 +1,23 @@
+/* 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 http://mozilla.org/MPL/2.0/. */
+/*
+ * The origin of this IDL file is:
+ * https://html.spec.whatwg.org/multipage/#messageport
+ */
+
+[Exposed=(Window,Worker)]
+interface MessagePort : EventTarget {
+  [Throws] undefined postMessage(any message, sequence<object> transfer);
+  [Throws] undefined postMessage(any message, optional StructuredSerializeOptions options = {});
+  undefined start();
+  undefined close();
+
+  // event handlers
+  attribute EventHandler onmessage;
+  attribute EventHandler onmessageerror;
+};
+
+dictionary StructuredSerializeOptions {
+  sequence<object> transfer = [];
+};