Change List.sort to not have a default parameter value.

sdk/lib/core/sequences.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.
 
 /**
  * An indexed sequence of elements of the same type.
  *
  * This is a primitive interface that any finite integer-indexable
  * sequence can implement.
  * It is intended for data structures where access by index is
@@ skipping 135 matching lines @@
   void addLast(E value) {
     throw new UnsupportedError(
         "Cannot add to an unmodifiable list");
   }
 
   void addAll(Collection<E> collection) {
     throw new UnsupportedError(
         "Cannot add to an unmodifiable list");
   }
 
-  void sort([Comparator<E> compare]) {
+  void sort([int compare(E a, E b)]) {
     throw new UnsupportedError(
         "Cannot modify an unmodifiable list");
   }
 
   void clear() {
     throw new UnsupportedError(
         "Cannot clear an unmodifiable list");
   }
 
   E removeAt(int index) {
@@ skipping 29 matching lines @@
   Sequence<E> _sequence;
   int _position;
   SequenceIterator(this._sequence) : _position = 0;
   bool get hasNext => _position < _sequence.length;
   E next() {
     if (hasNext) return _sequence[_position++];
     throw new StateError("No more elements");
   }
 }