Make data setter private on GrowableObjectArray.

runtime/lib/growable_array.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.
 
 class GrowableObjectArray<T> implements List<T> {
   factory GrowableObjectArray._uninstantiable() {
     throw const UnsupportedOperationException(
         "GrowableObjectArray can only be allocated by the VM");
   }
 
@@ skipping 90 matching lines @@
     } else {
       for (int i = new_length; i < length; i++) {
         this[i] = null;
       }
     }
     _setLength(new_length);
   }
 
   void _setLength(int new_length) native "GrowableObjectArray_setLength";
 
-  void set data(ObjectArray<T> array) native "GrowableObjectArray_setData";
+  void _setData(ObjectArray<T> array) native "GrowableObjectArray_setData";
 
   T operator [](int index) native "GrowableObjectArray_getIndexed";
 
   void operator []=(int index, T value) native "GrowableObjectArray_setIndexed";
 
   // The length of this growable array. It is always less than or equal to the
   // length of the object array, which itself is always greater than 0, so that
   // grow() does not have to check for a zero length object array before
   // doubling its size.
   void add(T value) {
@@ skipping 34 matching lines @@
   int lastIndexOf(T element, [int start = null]) {
     if (start === null) start = length - 1;
     return Arrays.lastIndexOf(this, element, start);
   }
 
   void _grow(int new_length) {
     var new_data = new ObjectArray<T>(new_length);
     for (int i = 0; i < length; i++) {
       new_data[i] = this[i];
     }
-    data = new_data;
+    _setData(new_data);
   }
 
   /**
    * Collection interface.
    */
 
   void forEach(f(T element)) {
     // TODO(srdjan): Use Collections.forEach(this, f);
     // Accessing the list directly improves DeltaBlue performance by 25%.
     for (int i = 0; i < length; i++) {
@@ skipping 57 matching lines @@
   T next() {
     if (!hasNext()) {
       throw const NoMoreElementsException();
     }
     return _array[_pos++];
   }
 
   final GrowableObjectArray<T> _array;
   int _pos;
 }