Build Observatory as part of runtime

runtime/observatory/lib/src/elements/debugger.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 debugger_page_element;
 
 import 'dart:html';
 import 'observatory_element.dart';
 import 'package:observatory/service.dart';
 import 'package:polymer/polymer.dart';
@@ skipping 115 matching lines @@
             print('Debugger command (not implemented): $text');
             text = '';
             break;
         }
       });
   }
 
   DebuggerInputElement.created() : super.created();
 }