Include the awaiter stack trace in the service protocol

runtime/observatory/lib/src/models/objects/frame.dart

 // Copyright (c) 2016, 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 models;
 
-enum FrameKind { regular, asyncCausal, asyncSuspensionMarker }
+enum FrameKind { regular, asyncCausal, asyncSuspensionMarker, asyncActivation }
 
 abstract class Frame {
   FrameKind get kind;
   String get marker;
   FunctionRef get function;
   SourceLocation get location;
 }