Roll Observatory packages and add a roll script

packages/code_transformers/lib/src/resolver.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 code_transformer.src.resolver;
 
 import 'dart:async';
 
 import 'package:analyzer/src/generated/ast.dart' show Expression;
 import 'package:analyzer/src/generated/constant.dart' show EvaluationResult;
@@ skipping 81 matching lines @@
   SourceFile getSourceFile(Element element);
 
   /// Creates a text edit transaction for the given element if it is able
   /// to be edited, returns null otherwise.
   ///
   /// The transaction contains the entire text of the source file where the
   /// element originated. If the element was from a library part then the
   /// source file is the part file rather than the library.
   TextEditTransaction createTextEditTransaction(Element element);
 }