include fields in verify_deps, refactor graph dfs

test/all_test.dart

-// Copyright (c) 2015, 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 'package:dart2js_info/info.dart';
-import 'package:test/test.dart';
-
-main() {
-  // TODO(sigmund): add more tests
-  group('parse', () {
-    test('empty', () {
-      var json = {
-        'elements': {
-          'library': {},
-          'class': {},
-          'function': {},
-          'field': {},
-          'typedef': {},
-        },
-        'holding': {},
-        'program': {'size': 10},
-      };
-
-      expect(new AllInfoJsonCodec().decode(json).program.size, 10);
-    });
-  });
-}