Do not JSON encode the 'result' of a service rpc.

runtime/vm/service.h

 // 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.
 
 #ifndef VM_SERVICE_H_
 #define VM_SERVICE_H_
 
 #include "include/dart_api.h"
 
 #include "vm/allocation.h"
@@ skipping 16 matching lines @@
  public:
   // Handles a message which is not directed to an isolate.
   static void HandleRootMessage(const Array& message);
 
   // Handles a message which is directed to a particular isolate.
   static void HandleIsolateMessage(Isolate* isolate, const Array& message);
 
   static bool NeedsEvents();
 
   static void HandleEvent(ServiceEvent* event);
-  static void HandleGCEvent(GCEvent* event);
 
   static void RegisterIsolateEmbedderCallback(
       const char* name,
       Dart_ServiceRequestCallback callback,
       void* user_data);
 
   static void RegisterRootEmbedderCallback(
       const char* name,
       Dart_ServiceRequestCallback callback,
       void* user_data);
@@ skipping 17 matching lines @@
                         const uint8_t* data,
                         intptr_t size);
 
   static EmbedderServiceHandler* isolate_service_handler_head_;
   static EmbedderServiceHandler* root_service_handler_head_;
 };
 
 }  // namespace dart
 
 #endif  // VM_SERVICE_H_