Add a "terse" argument to foldFrames().

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:unittest/unittest.dart';
 
@@ skipping 297 matching lines @@
 ''');
 
     var folded = trace.foldFrames((frame) => frame.member.startsWith('foo'));
     expect(folded.toString(), equals('''
 foo.dart 42:21                     notFoo
 foo.dart 1:100                     fooBottom
 bar.dart 10:20                     alsoNotFoo
 dart:async-patch/future.dart 9:11  fooBottom
 '''));
   });
+
+  test('.foldFrames with terse: true, folds core frames as well', () {
+    var trace = new Trace.parse('''
+#0 notFoo (foo.dart:42:21)
+#1 fooTop (bar.dart:0:2)
+#2 coreBottom (dart:async/future.dart:0:2)
+#3 alsoNotFoo (bar.dart:10:20)
+#4 fooTop (foo.dart:9:11)
+#5 coreBottom (dart:async-patch/future.dart:9:11)
+''');
+
+    var folded = trace.foldFrames((frame) => frame.member.startsWith('foo'),
+        terse: true);
+    expect(folded.toString(), equals('''
+foo.dart 42:21  notFoo
+dart:async      coreBottom
+bar.dart 10:20  alsoNotFoo
+dart:async      coreBottom
+'''));
+  });
 }