Give instances their own model class; move DartErrors out of instance-ref into their own error-ref.

runtime/bin/vmservice/observatory/lib/src/elements/observatory_element.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.
 
 library observatory_element;
 
 import 'dart:async';
 import 'dart:html';
 import 'package:observatory/app.dart';
 import 'package:polymer/polymer.dart';
@@ skipping 93 matching lines @@
 
   String formatSize(int bytes) => Utils.formatSize(bytes);
 
   String fileAndLine(Map frame) {
     var file = frame['script'].name;
     var shortFile = file.substring(file.lastIndexOf('/') + 1);
     return "${shortFile}:${frame['line']}";
   }
 
   int parseInt(String value) => int.parse(value);
-
-  bool isNull(ref) {
-    return ref != null && ref.serviceType == 'Null';
-  }
-
-  bool isSentinel(ref) {
-    return ref != null && ref.serviceType == 'Sentinel';
-  }
-
-  bool isError(ref) {
-    return ref != null && ref.serviceType == 'Error';
-  }
-
-  bool isInt(ref) {
-    return ref != null && (ref.serviceType == 'Smi' ||
-                           ref.serviceType == 'Mint' ||
-                           ref.serviceType == 'Bigint');
-  }
-
-  bool isBool(ref) {
-    return ref != null && ref.serviceType == 'Bool';
-  }
-
-  bool isString(ref) {
-    return ref != null && ref.serviceType == 'String';
-  }
-
-  bool isInstance(ref) {
-    return ref != null && ref.serviceType == 'Instance';
-  }
-
-  bool isDouble(ref) {
-    return ref != null && ref.serviceType == 'Double';
-  }
-
-  bool isList(ref) {
-    return ref != null && (ref.serviceType == 'GrowableObjectArray' ||
-            ref.serviceType == 'Array');
-  }
-
-  bool isType(ref) {
-    return ref != null && (ref.serviceType == 'Type');
-  }
-
-  bool isUnexpected(ref) {
-    if (ref == null) return false;
-    return (!['Null',
-              'Sentinel',
-              'Smi',
-              'Mint',
-              'Bigint',
-              'Bool',
-              'String',
-              'Double',
-              'Instance',
-              'GrowableObjectArray',
-              'Array',
-              'Type',
-              'Error'].contains(ref.serviceType));
-  }
 }