Add dead CodeRegionTable for tracking overwritten Dart code

runtime/bin/vmservice/client/lib/src/service/service.dart

 // Copyright (c) 2014, 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 service;
 
 /// A [ServiceObject] is an object known to the VM service and is tied
 /// to an owning [Isolate].
 abstract class ServiceObject extends Observable {
   Isolate _isolate;
@@ skipping 165 matching lines @@
       vm.isolates.update(m);
       return vm.isolates;
     case 'Script':
       return isolate.scripts.putIfAbsent(m);
     case 'Code':
       return isolate.codes.putIfAbsent(m);
     case 'Isolate':
       return vm.isolates.getIsolateFromMap(m);
     case 'Class':
       return isolate.classes.putIfAbsent(m);
+    case 'Function':
+      return isolate.functions.putIfAbsent(m);
   }
   return new ServiceMap.fromMap(isolate, m);
 }