Allow for embedder provided service request handlers

runtime/bin/vmservice_impl.cc

 // 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.
 
 #include "bin/vmservice_impl.h"
 
 #include "include/dart_api.h"
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
 #include "bin/isolate_data.h"
+#include "bin/platform.h"
 #include "bin/thread.h"
+#include "platform/json.h"
 
 namespace dart {
 namespace bin {
 
 #define RETURN_ERROR_HANDLE(handle)                             \
   if (Dart_IsError(handle)) {                                   \
     return handle;                                              \
   }
 
 #define SHUTDOWN_ON_ERROR(handle)                               \
@@ skipping 251 matching lines @@
     printf("Service exited with an error:\n%s\n", Dart_GetError(result));
   }
   Dart_ExitScope();
   Dart_ExitIsolate();
 }
 
 
 
 }  // namespace bin
 }  // namespace dart