Build Observatory as part of runtime

runtime/observatory/lib/src/app/location_manager.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.
 
 part of app;
 
 abstract class LocationManager extends Observable {
   final _initialPath = '/vm';
   ObservatoryApplication _app;
 
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     _go(window.location.pathname);
   }
 
   void _onLocationChange(PopStateEvent _) {
     _go(window.location.pathname);
   }
 
   /// Given an application url, generate a link for an anchor tag.
   String makeLink(String url) => url;
 }