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/TreeWalker.webidl

@@ -0,0 +1,34 @@
+/* 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-treewalker
+ */
+
+[Exposed=Window]
+interface TreeWalker {
+  [SameObject]
+  readonly attribute Node root;
+  [Constant]
+  readonly attribute unsigned long whatToShow;
+  [Constant]
+  readonly attribute NodeFilter? filter;
+  [Pure]
+           attribute Node currentNode;
+
+  [Throws]
+  Node? parentNode();
+  [Throws]
+  Node? firstChild();
+  [Throws]
+  Node? lastChild();
+  [Throws]
+  Node? previousSibling();
+  [Throws]
+  Node? nextSibling();
+  [Throws]
+  Node? previousNode();
+  [Throws]
+  Node? nextNode();
+};