Create generic check methods for RangeError causing checks.

sdk/lib/collection/queue.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.
 
 part of dart.collection;
 
 /**
  * A [Queue] is a collection that can be manipulated at both ends. One
  * can iterate over the elements of a queue through [forEach] or with
  * an [Iterator].
@@ skipping 409 matching lines @@
     return _table[(_tail - 1) & (_table.length - 1)];
   }
 
   E get single {
     if (_head == _tail) throw IterableElementError.noElement();
     if (length > 1) throw IterableElementError.tooMany();
     return _table[_head];
   }
 
   E elementAt(int index) {
-    if (index < 0 || index >= length) {
-      throw new RangeError.index(index, this);
-    }
+    RangeError.checkValidIndex(index, this);
     return _table[(_head + index) & (_table.length - 1)];
   }
 
   List<E> toList({ bool growable: true }) {
     List<E> list;
     if (growable) {
       list = new List<E>()..length = length;
     } else {
       list = new List<E>(length);
     }
@@ skipping 271 matching lines @@
     _queue._checkModification(_modificationCount);
     if (_position == _end) {
       _current = null;
       return false;
     }
     _current = _queue._table[_position];
     _position = (_position + 1) & (_queue._table.length - 1);
     return true;
   }
 }