Fix a couple bugs introduced in the last CL.

test/trace_test.dart

 // Copyright (c) 2013, 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 trace_test;
 
 import 'package:path/path.dart' as path;
 import 'package:stack_trace/stack_trace.dart';
 import 'package:test/test.dart';
 
@@ skipping 334 matching lines @@
 #1 top (dart:async/future.dart:0:2)
 #2 bottom (dart:core/uri.dart:1:100)
 ''');
 
       expect(trace.terse.toString(), equals('''
 dart:core  bottom
 '''));
     });
 
     test(".terse won't panic on an empty trace", () {
-      expect(Trace.parse("").terse.toString(), equals(""));
+      expect(new Trace.parse("").terse.toString(), equals(""));
     });
 
     test('.foldFrames folds frames together bottom-up', () {
       var trace = new Trace.parse('''
 #0 notFoo (foo.dart:42:21)
 #1 fooTop (bar.dart:0:2)
 #2 fooBottom (foo.dart:1:100)
 #3 alsoNotFoo (bar.dart:10:20)
 #4 fooTop (dart:io/socket.dart:5:10)
 #5 fooBottom (dart:async-patch/future.dart:9:11)
@@ skipping 55 matching lines @@
 ''');
 
       expect(trace.foldFrames((frame) => true).toString(), equals(r'''
 .g"cs$#:b";a#>sw{*{ul$"$xqwr`p
 %+j-?uppx<([j@#nu{{>*+$%x-={`{
 !e($b{nj)zs?cgr%!;bmw.+$j+pfj~
 '''));
     });
   });
 }