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/Attr.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/. */
+/*
+ * The origin of this IDL file is
+ * https://dom.spec.whatwg.org/#interface-attr
+ *
+ */
+
+[Exposed=Window]
+interface Attr : Node {
+  [Constant]
+  readonly attribute DOMString? namespaceURI;
+  [Constant]
+  readonly attribute DOMString? prefix;
+  [Constant]
+  readonly attribute DOMString localName;
+  [Constant]
+  readonly attribute DOMString name;
+  [CEReactions, Pure]
+           attribute DOMString value;
+
+  [Pure]
+  readonly attribute Element? ownerElement;
+
+  [Constant]
+  readonly attribute boolean specified; // useless; always returns true
+};