Make isEmpty a getter.

tests/compiler/dart2js/compiler_helper.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.
 // Test constant folding.
 
 library compiler_helper;
 
 import "dart:uri";
 
 import "../../../lib/compiler/implementation/elements/elements.dart" as lego;
@@ skipping 77 matching lines @@
   Expect.isTrue(regexp.hasMatch(generated),
                 '"$generated" does not match /$regexp/');
 }
 
 void compileAndDoNotMatch(String code, String entry, RegExp regexp) {
   String generated = compile(code, entry: entry);
   Expect.isFalse(regexp.hasMatch(generated),
                  '"$generated" has a match in /$regexp/');
 }
 
-int length(Link link) => link.isEmpty() ? 0 : length(link.tail) + 1;
+int length(Link link) => link.isEmpty ? 0 : length(link.tail) + 1;
 
 // Does a compile and then a match where every 'x' is replaced by something
 // that matches any variable, and every space is optional.
 void compileAndMatchFuzzy(String code, String entry, String regexp) {
   compileAndMatchFuzzyHelper(code, entry, regexp, true);
 }
  
 void compileAndDoNotMatchFuzzy(String code, String entry, String regexp) {
   compileAndMatchFuzzyHelper(code, entry, regexp, false);
 }
 
 void compileAndMatchFuzzyHelper(
     String code, String entry, String regexp, bool shouldMatch) {
   String generated = compile(code, entry: entry);
   final xRe = new RegExp('\\bx\\b');
   regexp = regexp.replaceAll(xRe, '(?:$anyIdentifier)');
   final spaceRe = new RegExp('\\s+');
   regexp = regexp.replaceAll(spaceRe, '(?:\\s*)');
   if (shouldMatch) {
     Expect.isTrue(new RegExp(regexp).hasMatch(generated));
   } else {
     Expect.isFalse(new RegExp(regexp).hasMatch(generated));
   }
 }