Roll Observatory packages and add a roll script

packages/code_transformers/lib/src/dart_sdk.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_transformers.src.dart_sdk;
 
 import 'dart:io' show Directory;
 
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/java_io.dart';
@@ skipping 27 matching lines @@
   Source mapDartUri(String dartUri) =>
       DartSourceProxy.wrap(super.mapDartUri(dartUri), Uri.parse(dartUri));
 }
 
 /// Dart SDK resolver which wraps all Dart sources to ensure they are tracked
 /// with URIs.
 class DartUriResolverProxy implements DartUriResolver {
   final DartUriResolver _proxy;
   DartUriResolverProxy(DartSdk sdk) : _proxy = new DartUriResolver(sdk);
 
-  Source resolveAbsolute(Uri uri) =>
-      DartSourceProxy.wrap(_proxy.resolveAbsolute(uri), uri);
+  Source resolveAbsolute(Uri uri, [Uri actualUri]) =>
+      DartSourceProxy.wrap(_proxy.resolveAbsolute(uri, actualUri), uri);
 
   DartSdk get dartSdk => _proxy.dartSdk;
 
   Source fromEncoding(UriKind kind, Uri uri) =>
       throw new UnsupportedError('fromEncoding is not supported');
 
   Uri restoreAbsolute(Source source) =>
       throw new UnsupportedError('restoreAbsolute is not supported');
 }
 
@@ skipping 189 matching lines @@
   'dart:async': '''
         class Future<T> {
           Future then(callback) {}
         class Stream<T> {}
   ''',
   'dart:html': '''
         library dart.html;
         class HtmlElement {}
         ''',
 };