Move Arrays class to private library.

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 new UnsupportedError(
         "GrowableObjectArray can only be allocated by the VM");
   }
 
@@ skipping 30 matching lines @@
   void removeMatching(bool test(T element)) {
     IterableMixinWorkaround.removeMatchingList(this, test);
   }
 
   void retainMatching(bool test(T element)) {
     IterableMixinWorkaround.removeMatchingList(this,
                                                (T element) => !test(element));
   }
 
   void setRange(int start, int length, List<T> from, [int startFrom = 0]) {
-    if (length < 0) {
-      throw new ArgumentError("negative length $length");
-    }
-    Arrays.copy(from, startFrom, this, start, length);
+    IterableMixinWorkaround.setRangeList(this, start, length, from, startFrom);
   }
 
   void removeRange(int start, int length) {
     if (length == 0) {
       return;
     }
     Arrays.rangeCheck(this, start, length);
     Arrays.copy(this,
                 start + length,
                 this,
@@ skipping 122 matching lines @@
     if (length == 1) return this[0];
     if (length == 0) throw new StateError("No elements");
     throw new StateError("More than one element");
   }
 
   T min([int compare(T a, T b)]) => IterableMixinWorkaround.min(this, compare);
 
   T max([int compare(T a, T b)]) => IterableMixinWorkaround.max(this, compare);
 
   int indexOf(T element, [int start = 0]) {
-    return Arrays.indexOf(this, element, start, length);
+    return IterableMixinWorkaround.indexOfList(this, element, start);
   }
 
   int lastIndexOf(T element, [int start = null]) {
-    if (start == null) start = length - 1;
-    return Arrays.lastIndexOf(this, element, start);
+    return IterableMixinWorkaround.lastIndexOfList(this, element, start);
   }
 
   void _grow(int new_length) {
     var new_data = new _ObjectArray(new_length);
     for (int i = 0; i < length; i++) {
       new_data[i] = this[i];
     }
     _setData(new_data);
   }
 
@@ skipping 112 matching lines @@
   }
 
   Set<T> toSet() {
     return new Set<T>.from(this);
   }
 
   Map<int, T> asMap() {
     return IterableMixinWorkaround.asMapList(this);
   }
 }