Clarify presentation of the target in retaining paths.

runtime/observatory/lib/src/elements/timeline_page.dart

 // Copyright (c) 2015, 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 timeline_page_element;
 
 import 'dart:async';
 import 'dart:html';
 import 'dart:convert';
 import 'package:observatory/service.dart' as S;
@@ skipping 178 matching lines @@
         return 'none';
       case _Profile.dart:
         return 'Dart Developer';
       case _Profile.vm:
         return 'VM Developer';
       case _Profile.all:
         return 'All';
       case _Profile.custom:
         return 'Custom';
     }
-    throw new Exception('Unkown Profile ${profile}');
+    throw new Exception('Unknown Profile ${profile}');
   }
 
   Future _refresh() async {
     S.VM vm = _vm as S.VM;
     await vm.reload();
     await vm.reloadIsolates();
     return _postMessage('refresh');
   }
 
   Future _clear() async {
@@ skipping 118 matching lines @@
     _availableStreams.clear();
     response['availableStreams']
         .forEach((String streamName) => _availableStreams.add(streamName));
     // Update the set of recorded streams.
     _recordedStreams.clear();
     response['recordedStreams']
         .forEach((String streamName) => _recordedStreams.add(streamName));
     _r.dirty();
   }
 }