Cleanup references to the old DDC repo

pkg/dev_compiler/tool/input_sdk/private/native_helper.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart._js_helper;
 
 
 /**
  * Sets a JavaScript property on an object.
  */
 void defineProperty(var obj, String property, var value) {
   JS('void',
       'Object.defineProperty(#, #, '
           '{value: #, enumerable: false, writable: true, configurable: true})',
       obj,
       property,
       value);
 }
 
 // Obsolete in dart dev compiler. Added only so that the same version of
 // dart:html can be used in dart2js an dev compiler.
 /*=F*/ convertDartClosureToJS /*<F>*/ (/*=F*/ closure, int arity) {
         return closure;
 }
 
 // Warning: calls to these methods need to be removed before custom elements
-// and cross-frame dom objects behave correctly in ddc.
-// See https://github.com/dart-lang/dev_compiler/issues/517
+// and cross-frame dom objects behave correctly in ddc
+// https://github.com/dart-lang/sdk/issues/28326
 setNativeSubclassDispatchRecord(proto, interceptor) { }
 findDispatchTagForInterceptorClass(interceptorClassConstructor) {}
 makeLeafDispatchRecord(interceptor) {}