Roll Observatory packages and add a roll script

packages/dart_style/lib/src/chunk.dart

 // Copyright (c) 2014, 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 dart_style.src.chunk;
 
 import 'fast_hash.dart';
 import 'nesting_level.dart';
 import 'rule/rule.dart';
 
@@ skipping 348 matching lines @@
   /// output. This way, commented out chunks of code do not get erroneously
   /// re-indented.
   final bool flushLeft;
 
   /// Whether this comment is an inline block comment.
   bool get isInline => linesBefore == 0 && !isLineComment;
 
   SourceComment(this.text, this.linesBefore,
       {this.isLineComment, this.flushLeft});
 }