Implement getRange (returning an Iterable).

runtime/lib/typeddata.dart

 // Copyright (c) 2013, 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.
 
 // patch classes for Int8List ..... Float64List and ByteData implementations.
 
 patch class Int8List {
   /* patch */ factory Int8List(int length) {
     return new _Int8Array(length);
   }
@@ skipping 458 matching lines @@
 
   List sublist(int start, [int end]) {
     if (end == null) end = length;
     int length = end - start;
     _rangeCheck(this.length, start, length);
     List result = _createList(length);
     result.setRange(0, length, this, start);
     return result;
   }
 
-  List getRange(int start, int length) {
-    return sublist(start, start + length);
+  Iterable getRange(int start, [int end]) {
+    return IterableMixinWorkaround.getRangeList(this, start, end);
   }
 
   void setRange(int start, int length, List from, [int startFrom = 0]) {
     if (!_setRange(start, length, from, startFrom)) {
       IterableMixinWorkaround.setRangeList(this, start,
                                            length, from, startFrom);
     }
   }
 
 
@@ skipping 2588 matching lines @@
     return value;
   }
   return object;
 }
 
 
 void _throwRangeError(int index, int length) {
   String message = "$index must be in the range [0..$length)";
   throw new RangeError(message);
 }