Changed interfaces to abstract classes where possible in {lib,samples,pkg}

lib/utf/utf_core.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.
 
 /**
  * Provide a list of Unicode codepoints for a given string.
  */
 List<int> stringToCodepoints(String str) {
   List<int> codepoints;
   // TODO _is16BitCodeUnit() is used to work around a bug with dart2js
@@ skipping 222 matching lines @@
       new _ListRangeIteratorImpl(_source, _offset, _offset + _length);
 
   int get length => _length;
 }
 
 /**
  * The _ListRangeIterator provides more capabilities than a standard iterator,
  * including the ability to get the current position, count remaining items,
  * and move forward/backward within the iterator.
  */
-interface _ListRangeIterator extends Iterator<int> {
+abstract class _ListRangeIterator extends Iterator<int> {

[ngeoffray, 2012/09/12 10:41:47]

Should that be implements?

[bakster, 2012/09/12 10:45:49]

Done.

   bool hasNext();
   int next();
   int get position;
   void backup([by]);
   int get remaining;
   void skip([count]);
 }
 
 class _ListRangeIteratorImpl implements _ListRangeIterator {
   final List<int> _source;
@@ skipping 12 matching lines @@
     _offset -= by;
   }
 
   int get remaining => _end - _offset;
 
   void skip([int count = 1]) {
     _offset += count;
   }
 }