Revert "Parts must start with 'part of'" and "Attempt to fix VM build"

dart/lib/compiler/implementation/lib/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 js_helper;
-
 String typeNameInChrome(obj) {
   String name = JS('String', "#.constructor.name", obj);
   if (name == 'Window') return 'DOMWindow';
   if (name == 'CanvasPixelArray') return 'Uint8ClampedArray';
   if (name == 'WebKitMutationObserver') return 'MutationObserver';
   return name;
 }
 
 String typeNameInSafari(obj) {
   String name = JS('String', '#', constructorNameFallback(obj));
@@ skipping 321 matching lines @@
   }
   return result;
 }
 
 /**
  * Called by the compiler to setup [_dynamicMetadata].
  */
 void dynamicSetMetadata(List<List<String>> inputTable) {
   _dynamicMetadata = buildDynamicMetadata(inputTable);
 }