Reapply change to hide VM-only List implementation classes.

runtime/lib/array_patch.dart

Index: runtime/lib/array_patch.dart
diff --git a/runtime/lib/array_patch.dart b/runtime/lib/array_patch.dart
index 502723685bd0961699da040bc0d59ba884059f6c..1e48eccfeef3f81bdba53a6c11efe14a17f6801b 100644
--- a/runtime/lib/array_patch.dart
+++ b/runtime/lib/array_patch.dart
@@ -2,19 +2,20 @@
 // 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.
 
-// Note that optimizing compiler depends on the algorithm which returns
-// a GrowableObjectArray if length is null, otherwise returns fixed size array.
+// Note that optimizing compiler depends on the algorithm which
+// returns a _GrowableObjectArray if length is null, otherwise returns
+// fixed size array.
 patch class ListImplementation<E> {
   /* patch */ factory List([int length = null]) {
     if (length === null) {
-      return new GrowableObjectArray<E>();
+      return new _GrowableObjectArray<E>();
     } else {
-      return new ObjectArray<E>(length);
+      return new _ObjectArray<E>(length);
     }
   }
 
   /* patch */ static _from(Iterable other) {
-    GrowableObjectArray list = new GrowableObjectArray();
+    _GrowableObjectArray list = new _GrowableObjectArray();
     for (final e in other) {
       list.add(e);
     }