Make isEmpty a getter.

tests/compiler/dart2js/parser_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.
 
 library parser_helper;
 
 import "dart:uri";
 
 import "../../../lib/compiler/implementation/elements/elements.dart";
 import "../../../lib/compiler/implementation/tree/tree.dart";
@@ skipping 22 matching lines @@
           new Uri.fromComponents(scheme: "source"),
           new MockFile(text));
   LibraryElement library = new LibraryElement(script);
   library.canUseNative = true;
   NodeListener listener = new NodeListener(lc, library.entryCompilationUnit);
   Parser parser = new Parser(listener);
   Token endToken = parseMethod(parser, tokens);
   assert(endToken.kind == EOF_TOKEN);
   Node node = listener.popNode();
   Expect.isNotNull(node);
-  Expect.isTrue(listener.nodes.isEmpty(), 'Not empty: ${listener.nodes}');
+  Expect.isTrue(listener.nodes.isEmpty, 'Not empty: ${listener.nodes}');
   return node;
 }
 
 Node parseStatement(String text) =>
   parseBodyCode(text, (parser, tokens) => parser.parseStatement(tokens));
 
 Node parseFunction(String text, Compiler compiler) {
   Element element = parseUnit(text, compiler, compiler.mainApp).head;
   Expect.isNotNull(element);
   Expect.equals(ElementKind.FUNCTION, element.kind);
@@ skipping 24 matching lines @@
 NodeList fullParseUnit(String source) {
   return parseBodyCode(source, (parser, tokens) => parser.parseUnit(tokens));
 }
 
 // TODO(ahe): We define this method to avoid having to import
 // the scanner in the tests. We should move SourceString to another
 // location instead.
 SourceString buildSourceString(String name) {
   return new SourceString(name);
 }