Support some usages of empty classes.

tests/compiler/dart2js/unparser_test.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.
 
 #import('dart:uri');
 #import('parser_helper.dart');
 #import("../../../lib/compiler/compiler.dart");
 #import("../../../lib/compiler/implementation/tree/tree.dart");
 
 testUnparse(String statement) {
@@ skipping 169 matching lines @@
 testVariableDefinitions() {
   testDart2Dart('main(){final var x,y; final String s;}');
   testDart2Dart('foo(f,g){}main(){foo(1,2);}');
   testDart2Dart('foo(f(arg)){}main(){foo(main);}');
   // A couple of static/finals inside a class.
   testDart2Dart('main(){A.a; A.b;}class A{static final String a="5";'
       'static final String b="4";}');
   // Class member of typedef-ed function type.
   // Maybe typedef should be included in the result too, but it
   // works fine without it.
-  testDart2Dart('typedef void foofunc(arg);'
-      'class A {'
-        'final foofunc handler;'
-        'A(foofunc this.handler);'
-      '}'
-      'main() {new A((arg) {});}', (result) {
-        Expect.equals(
-            'main(){new A((arg){});}'
-            'class A{A(foofunc this.handler);final foofunc handler;}', result);
-      });
+  testDart2Dart(
+    'main(){new A((arg){});}typedef void foofunc(arg);'
+    'class A{A(foofunc this.handler);final foofunc handler;}');
 }
 
 testGetSet() {
   // Top-level get/set.
   testDart2Dart('get foo(){return 5;}set foo(arg){}main(){foo; foo=5;}');
   // Field get/set.
   testDart2Dart('main(){var a=new A(); a.foo; a.foo=5;}'
       'class A{set foo(a){}get foo(){return 5;}}');
   // Typed get/set.
   testDart2Dart('String get foo(){return "a";}main(){foo;}');
@@ skipping 216 matching lines @@
   testFactoryConstructor();
   testTopLevelField();
   testAbstractClass();
   testConflictLibraryClassRename();
   testNoConflictSendsRename();
   testConflictSendsRename();
   // Disabled with revert of https://chromiumcodereview.appspot.com/10824062/
   // testDefaultClassWithArgs();
   testClassExtendsWithArgs();
 }