Roll Observatory packages and add a roll script

source_maps/lib/source_maps.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 to create and parse source maps.
-///
-/// Create a source map using [SourceMapBuilder]. For example:
-///     var json = (new SourceMapBuilder()
-///         ..add(inputSpan1, outputSpan1)
-///         ..add(inputSpan2, outputSpan2)
-///         ..add(inputSpan3, outputSpan3)
-///         .toJson(outputFile);
-///
-/// Use the source_span package's [SourceSpan] and [SourceFile] classes to
-/// specify span locations.
-///
-/// Parse a source map using [parse], and call `spanFor` on the returned mapping
-/// object. For example:
-///     var mapping = parse(json);
-///     mapping.spanFor(outputSpan1.line, outputSpan1.column)
-///
-/// ## Getting the code ##
-///
-/// This library is distributed as a [pub][] package. To install this package,
-/// add the following to your `pubspec.yaml` file:
-///
-///     dependencies:
-///       source_maps: any
-///
-/// After you run `pub install`, you should be able to access this library by
-/// importing `package:source_maps/source_maps.dart`.
-///
-/// For more information, see the
-/// [source_maps package on pub.dartlang.org][pkg].
-///
-/// [pub]: http://pub.dartlang.org
-/// [pkg]: http://pub.dartlang.org/packages/source_maps
-library source_maps;
-
-export "builder.dart";
-export "parser.dart";
-export "printer.dart";
-export "refactor.dart";
-export 'src/source_map_span.dart';