Roll Observatory packages and add a roll script

packages/web_components/lib/build/test_compatibility.dart

 // Copyright (c) 2015, 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.
 
 /// Some Transformers to maintain compatibility with the new `test` package,
 /// since it doesn't use normal dart script tags in html. We get around this by
 /// using two transformers:
 ///   - A transformer to convert <lint rel="x-dart-test"> intro dart script tags
 ///     so that they can be processed by the rest of the transformers normally.
 ///   - A second transformer to convert the output back, so that the `test`
@@ skipping 59 matching lines @@
 
   _EntryPointOnlyTransformer(this.entryPoints) : super();
 
   bool isPrimary(AssetId id) {
     if (!id.path.startsWith('test/')) return false;
     if (entryPoints != null) return entryPoints.contains(id.path);
     // If no entry point is supplied, then any html file is an entry point.
     return id.path.endsWith('.html');
   }
 }