Revert "Build Observatory with runtime"

runtime/bin/vmservice/observatory/lib/src/elements/curly_block.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 curly_block_element;
 
 import 'package:polymer/polymer.dart';
 
 @CustomTag('curly-block')
 class CurlyBlockElement extends PolymerElement {
@@ skipping 19 matching lines @@
       return;
     }
     if (callback != null) {
       busy = true;
       callback(!expanded, doneCallback);
     } else {
       expanded = !expanded;
     }
   }
 }