Avoid to return null in anyRef if object is not known

runtime/observatory/lib/src/elements/helpers/any_ref.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.
 
 import 'dart:html';
 import 'package:observatory/models.dart' as M;
 import 'package:observatory/src/elements/class_ref.dart';
 import 'package:observatory/src/elements/code_ref.dart';
 import 'package:observatory/src/elements/context_ref.dart';
 import 'package:observatory/src/elements/error_ref.dart';
 import 'package:observatory/src/elements/field_ref.dart';
 import 'package:observatory/src/elements/function_ref.dart';
 import 'package:observatory/src/elements/helpers/rendering_scheduler.dart';
+import 'package:observatory/src/elements/helpers/uris.dart';
 import 'package:observatory/src/elements/icdata_ref.dart';
 import 'package:observatory/src/elements/instance_ref.dart';
 import 'package:observatory/src/elements/megamorphiccache_ref.dart';
 import 'package:observatory/src/elements/library_ref.dart';
 import 'package:observatory/src/elements/local_var_descriptors_ref.dart';
 import 'package:observatory/src/elements/objectpool_ref.dart';
 import 'package:observatory/src/elements/pc_descriptors_ref.dart';
 import 'package:observatory/src/elements/script_ref.dart';
 import 'package:observatory/src/elements/sentinel_value.dart';
 import 'package:observatory/src/elements/type_arguments_ref.dart';
@@ skipping 35 matching lines @@
     } else if (ref is M.Sentinel) {
       return new SentinelValueElement(ref, queue: queue);
     } else if (ref is M.ScriptRef) {
       return new ScriptRefElement(isolate, ref, queue: queue);
     } else if (ref is M.TypeArgumentsRef) {
       return new TypeArgumentsRefElement(isolate, ref, queue: queue);
     } else if (ref is M.TokenStreamRef) {
       return new TokenStreamRefElement(isolate, ref, queue: queue);
     } else if (ref is M.UnknownObjectRef) {
       return new UnknownObjectRefElement(isolate, ref, queue: queue);
+    } else {
+      return new AnchorElement(href: Uris.inspect(isolate, object: ref))
+        ..text = 'object';
     }
   }
-  return null;
+  throw new Exception('Unknown runtimeType (${ref.runtimeType})');

[rmacnak, 2016/09/01 22:24:51]

Unknown ref

 }