Move NullError into interceptors

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

 // Copyright (c) 2013, 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.
 
 library dart._js_helper;
 
 import 'dart:collection';
 
 import 'dart:_debugger' show stackTraceMapper;
 
@@ skipping 558 matching lines @@
 
 throwAbstractClassInstantiationError(className) {
   throw new AbstractClassInstantiationError(className);
 }
 
 @NoInline()
 throwConcurrentModificationError(collection) {
   throw new ConcurrentModificationError(collection);
 }
 
-@JsPeerInterface(name: 'TypeError')
-class NullError extends Interceptor implements NoSuchMethodError {
-  StackTrace get stackTrace => Primitives.extractStackTrace(this);
-
-  String toString() {
-    // TODO(vsm): Distinguish between null reference errors and other
-    // TypeErrors.  We should not get non-null TypeErrors from DDC code,
-    // but we may from native JavaScript.
-    var message = JS('String', '#.message', this);
-    return "NullError: $message";
-  }
-}
-
 class JsNoSuchMethodError extends Error implements NoSuchMethodError {
   final String _message;
   final String _method;
   final String _receiver;
 
   JsNoSuchMethodError(this._message, match)
       : _method = match == null ? null : JS('String|Null', '#.method', match),
         _receiver =
             match == null ? null : JS('String|Null', '#.receiver', match);
 
@@ skipping 313 matching lines @@
   // we have no way of telling the compiler yet, so it will generate an extra
   // layer of indirection that wraps the SyncIterator.
   _jsIterator() => JS('', '#(...#)', _generator, _args);
 
   Iterator<E> get iterator => new SyncIterator<E>(_jsIterator());
 }
 
 class BooleanConversionAssertionError extends AssertionError {
   toString() => 'Failed assertion: boolean expression must not be null';
 }