Implement async file API on top of isolates.

tests/corelib/src/ListSetRangeTest.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.
 
 main() {
   var list = [];
   list.setRange(0, 0, const []);
   list.setRange(0, 0, []);
   list.setRange(0, 0, const [], 1);
   list.setRange(0, 0, [], 1);
@@ skipping 34 matching lines @@
   list.setRange(2, 2, [5, 6, 7, 8]);
   Expect.listEquals([1, 2, 5, 6], list);
 
   expectIOORE(() { list.setRange(4, 1, [5, 6, 7, 8]); });
   Expect.listEquals([1, 2, 5, 6], list);
 
   list.setRange(1, 2, [9, 10, 11, 12]);
   Expect.listEquals([1, 9, 10, 6], list);
 
   testNegativeIndices();
+
+  testNonExtendableList();
 }
 
 void expectIOORE(Function f) {
   Expect.throws(f, (e) => e is IndexOutOfRangeException);
 }
 
 void testNegativeIndices() {
   var list = [1, 2];
   expectIOORE(() { list.setRange(-1, 1, [1]); });
   expectIOORE(() { list.setRange(0, 1, [1], -1); });
 
   // A negative length throws an IllegalArgumentException.
   Expect.throws(() { list.setRange(0, -1, [1]); },
       (e) => e is IllegalArgumentException);
 
   Expect.throws(() { list.setRange(-1, -1, [1], -1); },
       (e) => e is IllegalArgumentException);
   Expect.listEquals([1, 2], list);
 
   // A zero length prevails, and does not throw an exception.
   list.setRange(-1, 0, [1]);
   Expect.listEquals([1, 2], list);
 
   list.setRange(0, 0, [1], -1);
   Expect.listEquals([1, 2], list);
 }
+
+void testNonExtendableList() {
+  var list = new List<int>(6);
+  Expect.listEquals([null, null, null, null, null, null], list);
+  list.setRange(0, 3, [1, 2, 3, 4]);
+  list.setRange(3, 3, [1, 2, 3, 4]);
+  Expect.listEquals([1, 2, 3, 1, 2, 3], list);
+}