Implement toString for ImmutableArray and GrowableObjectArray (Issue 952)

runtime/lib/array.dart

 // Copyright (c) 2011, 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 ListFactory<E> {
 
   factory List.from(Iterable<E> other) {
     GrowableObjectArray<E> list = new GrowableObjectArray<E>();
     for (final e in other) {
       list.add(e);
@@ skipping 216 matching lines @@
   bool isEmpty() {
     return this.length === 0;
   }
 
   void sort(int compare(E a, E b)) {
     throw const UnsupportedOperationException(
         "Cannot modify an immutable array");
   }
 
   String toString() {
-    return "ImmutableArray";
+    return Arrays.asString(this);
   }
 
   int indexOf(E element, [int start = 0]) {
     return Arrays.indexOf(this, element, start, this.length);
   }
 
   int lastIndexOf(E element, [int start = null]) {
     if (start === null) start = length - 1;
     return Arrays.lastIndexOf(this, element, start);
   }
@@ skipping 52 matching lines @@
     if (!hasNext()) {
       throw const NoMoreElementsException();
     }
     return _array[_pos++];
   }
 
   final List<E> _array;
   final int _length;  // Cache array length for faster access.
   int _pos;
 }