Roll Observatory packages and add a roll script

packages/web_components/test/init_web_components_test.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.
+@initializeTracker
+library web_components.test.init_web_components_test;
+
+import 'package:unittest/html_config.dart';
+import 'package:unittest/unittest.dart';
+import 'package:initialize/initialize.dart' show LibraryIdentifier;
+import 'package:initialize/src/initialize_tracker.dart';
+import 'package:web_components/web_components.dart';
+
+const String importPath = 'my_import.html';
+
+main() {
+  useHtmlConfiguration();
+
+  test('can initialize scripts from html imports', () {
+    return initWebComponents().then((_) {
+      var expectedInitializers = [
+        const LibraryIdentifier(
+            #web_components.test.deps.b, null, 'deps/b.dart'),
+        // This one changes based on deploy mode because its an inline script.
+        const LibraryIdentifier(#web_components.test.deps.c, null, deployMode
+            ? 'init_web_components_test.html.0.dart'
+            : 'deps/c.html'),
+        const LibraryIdentifier(
+            #web_components.test.deps.a, null, 'deps/a.dart'),
+        const LibraryIdentifier(#web_components.test.init_web_components_test,
+            null, 'init_web_components_test.dart'),
+      ];
+      expect(InitializeTracker.seen, expectedInitializers);
+    });
+  });
+}