Re-enable NodeIterator

tools/dom/idl/dart/dart.idl

 // This file introduces / supplements and forces Dart declarations.
 
 [Supplemental,
  Constructor]
 interface AudioContext {
   // TODO(ager): Auto-generate this custom method when the info about retaining
   // typed arrays is in the IDL.
   [Custom] void decodeAudioData(ArrayBuffer audioData, AudioBufferCallback successCallback, AudioBufferCallback errorCallback);
 };
 
@@ skipping 330 matching lines @@
 interface ImageBitmapFactories {};
 
 // See https://chromiumcodereview.appspot.com/15901002 for the V8 implementation of
 // TextEncoder/TextDecoder
 [Suppressed]
 interface TextEncoder {};
 
 [Suppressed]
 interface TextDecoder {};
 
-// TODO(jacobr): renable these as part of fixing dartbug.com/12537
-// We need to apply changes analogous to https://chromiumcodereview.appspot.com/21274004
-// to the Dart bindings so that we can reenable NodeIterator and TreeWalker
-[Suppressed]
-interface NodeIterator {};
-
-[Suppressed]
-interface TreeWalker {};
-
 [Supplemental]
 interface Window : EventTarget {};