6436314: Vector could be created with appropriate size in DefaultComboBoxModel

Reviewed-by: alexsch, alexp

src/share/classes/javax/swing/DefaultComboBoxModel.java

 /*
- * Copyright (c) 1998, 2004, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -55,8 +55,7 @@ public class DefaultComboBoxModel<E> extends AbstractListModel<E> implements Mut
      * @param items  an array of Object objects
      */
     public DefaultComboBoxModel(final E items[]) {
-        objects = new Vector<E>();
-        objects.ensureCapacity( items.length );
+        objects = new Vector<E>(items.length);
 
         int i,c;
         for ( i=0,c=items.length;i<c;i++ )