Add a QueueList class to the collection package.

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 569 matching lines @@
 
   /**
    * Rounds [number] up to the nearest power of 2.
    *
    * If [number] is a power of 2 already, it is returned.
    *
    * Only works for positive numbers.
    */
   static int _nextPowerOf2(int number) {
     assert(number > 0);
-    number = (number << 2) - 1;
+    number = (number << 1) - 1;
     for(;;) {
       int nextNumber = number & (number - 1);
       if (nextNumber == 0) return number;
       number = nextNumber;
     }
   }
 
   /** Check if the queue has been modified during iteration. */
   void _checkModification(int expectedModificationCount) {
     if (expectedModificationCount != _modificationCount) {
@@ skipping 70 matching lines @@
       int firstPartSize = _table.length - _head;
       target.setRange(0, firstPartSize, _table, _head);
       target.setRange(firstPartSize, firstPartSize + _tail, _table, 0);
       return _tail + firstPartSize;
     }
   }
 
   /** Grows the table even if it is not full. */
   void _preGrow(int newElementCount) {
     assert(newElementCount >= length);
+
+    // Add some extra room to ensure that there's room for more elements after
+    // expansion.
+    newElementCount += newElementCount >> 1;
     int newCapacity = _nextPowerOf2(newElementCount);
     List<E> newTable = new List<E>(newCapacity);
     _tail = _writeToList(newTable);
     _table = newTable;
     _head = 0;
   }
 }
 
 /**
  * Iterator for a [ListQueue].
@@ skipping 19 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;
   }
 }