Roll Observatory packages and add a roll script

packages/analyzer/example/parser_driver.dart

+#!/usr/bin/env 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.
+
+import 'dart:io';
+
+import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/src/generated/error.dart';
+import 'package:analyzer/src/generated/parser.dart';
+import 'package:analyzer/src/generated/scanner.dart';
+
+main(List<String> args) {
+  print('working dir ${new File('.').resolveSymbolicLinksSync()}');
+
+  if (args.length == 0) {
+    print('Usage: parser_driver [files_to_parse]');
+    exit(0);
+  }
+
+  for (var arg in args) {
+    _parse(new File(arg));
+  }
+}
+
+_parse(File file) {
+  var src = file.readAsStringSync();
+  var errorListener = new _ErrorCollector();
+  var reader = new CharSequenceReader(src);
+  var scanner = new Scanner(null, reader, errorListener);
+  var token = scanner.tokenize();
+  var parser = new Parser(null, errorListener);
+  var unit = parser.parseCompilationUnit(token);
+
+  var visitor = new _ASTVisitor();
+  unit.accept(visitor);
+
+  for (var error in errorListener.errors) {
+    print(error);
+  }
+}
+
+class _ASTVisitor extends GeneralizingAstVisitor {
+  visitNode(AstNode node) {
+    print('${node.runtimeType} : <"$node">');
+    return super.visitNode(node);
+  }
+}
+
+class _ErrorCollector extends AnalysisErrorListener {
+  List<AnalysisError> errors;
+  _ErrorCollector() : errors = new List<AnalysisError>();
+  onError(error) => errors.add(error);
+}