Build Observatory as part of runtime

runtime/bin/vmservice/observatory/lib/src/elements/action_link.dart

-// Copyright (c) 2013, 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 action_link_element;
-
-import 'package:polymer/polymer.dart';
-
-@CustomTag('action-link')
-class ActionLinkElement extends PolymerElement {
-  ActionLinkElement.created() : super.created();
-
-  @observable bool busy = false;
-  @published var callback = null;
-  @published String label = 'action';
-  @published String color = null;
-
-  void doAction(var a, var b, var c) {
-    if (busy) {
-      return;
-    }
-    if (callback != null) {
-      busy = true;
-      // TODO(turnidge): Track down why adding a dummy argument makes
-      // this work but having a no-argument callback doesn't.
-      callback(null).whenComplete(() {
-          busy = false;
-        });
-    }
-  }
-}