Make isEmpty a getter.

tests/compiler/dart2js/begin_end_token_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.
 
 #import('parser_helper.dart');
 #import("../../../lib/compiler/implementation/scanner/scannerlib.dart");
 #import("../../../lib/compiler/implementation/tree/tree.dart");
 
 
 void testNode(Node node, String expected, String text, [bool hard = true]) {
@@ skipping 126 matching lines @@
   SendSet sendSet;
   String text;
 
   text = "a.b++";
   node = testExpression(text);
   // Should parse as: (a.b)++.
   Expect.isNotNull(sendSet = node.asSendSet());
   testNode(sendSet.receiver, "a", text);
   testNode(sendSet.selector, "b", text);
   testNode(sendSet.assignmentOperator, "++", text);
-  Expect.isTrue(sendSet.arguments.isEmpty());
+  Expect.isTrue(sendSet.arguments.isEmpty);
 
   text = "++a[b]";
   // TODO(johnniwinther): SendSet generates the wrong end token in the following
   // line. We should have [:testExpression(text):] instead of
   // [:testExpression(text, "++a"):].
   node = testExpression(text, "++a");
   Expect.isNotNull(sendSet = node.asSendSet());
   testNode(sendSet.receiver, "a", text);
   testNode(sendSet.selector, "[]", text, false); // Operator token is synthetic.
   testNode(sendSet.assignmentOperator, "++", text);
   testNode(sendSet.arguments.head, "b", text);
 
   text = "a[b]++";
   node = testExpression(text);
   Expect.isNotNull(sendSet = node.asSendSet());
   testNode(sendSet.receiver, "a", text);
   testNode(sendSet.selector, "[]", text, false); // Operator token is synthetic.
   testNode(sendSet.assignmentOperator, "++", text);
   testNode(sendSet.arguments.head, "b", text);
 }
 
 void main() {
   testUnaryExpression();
   testAssignment();
   testIndex();
   testPostfix();
 }