Modify scanner and parser to be standalone packages.

pkg/dart_parser/test/parser_suite.dart

+// Copyright (c) 2016, 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.md file.
+
+import 'package:testing/testing.dart';

[Siggi Cherem (dart-lang), 2017/01/12 21:56:04]

I'm curious to take a look at this package in more detail. Is it already in
fe_integration or CLs where I could take a look?

[ahe, 2017/01/13 07:16:21]

I have outstanding reviews for landing it, but you can see most of it here:
https://github.com/peter-ahe-google/testing. In addition, take a look at CL
2627723006 and follow its dependencies (or just look at my open code reviews, I
just cleaned up the list).

+
+import 'package:scanner/scanner.dart';
+
+import 'package:scanner/testing/scanner_chain.dart';
+
+import 'package:parser/parser.dart';
+
+Future<ChainContext> createContext(
+    Chain suite, Map<String, String> enviroment) async {
+  return new ScannerContext();
+}
+
+class ScannerContext extends ChainContext {
+  final List<Step> steps = const <Step>[
+      const Read(),
+      const Scan(),
+      const Parse(),
+  ];
+}
+
+class Parse extends Step<ScannerResult, Null, ChainContext> {
+  const Parse();
+
+  String get name => "parse";
+
+  Future<Result<Null>> run(
+      ScannerResult result, ChainContext context) async {
+    try {
+      List<ParserError> errors = parse(result.tokens);
+      if (errors.isNotEmpty) {
+        return fail(null, errors.join("\n"));
+      }
+    } on ParserError catch (e, s) {
+      return fail(null, e, s);
+    }
+    return pass(null);
+  }
+}
+
+main(List<String> arguments) => runMe(arguments, createContext);