Make first and last getters.

tests/corelib/queue_test.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.
 
 #library("QueueTest.dart");
 #import("dart:coreimpl");
 
 class QueueTest {
 
   static testMain() {
@@ skipping 72 matching lines @@
     try {
       queue.removeLast();
     } on EmptyQueueException catch (e) {
       exception = e;
     }
     Expect.equals(true, exception != null);
     Expect.equals(0, queue.length);
 
     queue.addFirst(1);
     queue.addFirst(2);
-    Expect.equals(2, queue.first());
-    Expect.equals(1, queue.last());
+    Expect.equals(2, queue.first);
+    Expect.equals(1, queue.last);
 
     queue.addLast(3);
-    Expect.equals(3, queue.last());
+    Expect.equals(3, queue.last);
     bool isGreaterThanOne(int value) {
       return (value > 1);
     }
 
     other = queue.filter(isGreaterThanOne);
     checkQueue(other, 2, 5);
 
     testAddAll();
   }
 
@@ skipping 70 matching lines @@
       entry1 = entry1.nextEntry();
       entry2 = entry2.nextEntry();
     }
     Expect.equals(null, entry2);
   }
 }
 
 main() {
   QueueTest.testMain();
 }