Make isEmpty a getter.

pkg/dartdoc/lib/mirrors_util.dart

 // Copyright (c) 2012, 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('mirrors.util');
 
 // TODO(rnystrom): Use "package:" URL (#4968).
 #import('mirrors.dart');
 #import('../../../lib/compiler/implementation/util/characters.dart');
 
@@ skipping 101 matching lines @@
       } else {
         queue.addFirst(type.superclass);
       }
     }
     queue.addAll(type.interfaces);
     return type;
   }
 
   InterfaceMirror next() {
     InterfaceMirror type;
-    if (queue.isEmpty()) {
+    if (queue.isEmpty) {
       if (object === null) {
         throw new NoMoreElementsException();
       }
       type = object;
       object = null;
       return type;
     } else {
       return push(queue.removeFirst());
     }
   }
 
-  bool get hasNext => !queue.isEmpty() || object !== null;
+  bool get hasNext => !queue.isEmpty || object !== null;
 }