Add Function based profile tree

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;
 
@@ skipping 58 matching lines @@
   void back() {
     window.history.go(-1);
   }
 
   /// Go forward.
   void forward() {
     window.history.go(1);
   }
 
   /// Handle clicking on an application url link.
-  void onGoto(MouseEvent event, var detail, Element target) {
+  void onGoto(MouseEvent event) {
+    var target = event.target;
     var href = target.attributes['href'];
     if (event.button > 0 || event.metaKey || event.ctrlKey ||
         event.shiftKey || event.altKey) {
       // Not a left-click or a left-click with a modifier key:
       // Let browser handle.
       return;
     }
     go(href);
     event.preventDefault();
   }
@@ skipping 38 matching lines @@
     _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;
 }