Remove legacy restart code

runtime/lib/vmservice.cc

 // Copyright (c) 2015, 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 "vm/bootstrap_natives.h"
 #include "vm/dart_api_impl.h"
 #include "vm/datastream.h"
 #include "vm/exceptions.h"
 #include "vm/flags.h"
 #include "vm/growable_array.h"
@@ skipping 104 matching lines @@
   // TODO(turnidge): Throw an exception when the return value is false?
   bool result = PortMap::PostMessage(
       new Message(sp.Id(), data, writer.BytesWritten(), Message::kOOBPriority));
   return Bool::Get(result).raw();
 }
 
 
 DEFINE_NATIVE_ENTRY(VMService_SendRootServiceMessage, 1) {
   GET_NON_NULL_NATIVE_ARGUMENT(Array, message, arguments->NativeArgAt(0));
   if (FLAG_support_service) {
-    Service::HandleRootMessage(message);
+    return Service::HandleRootMessage(message);
   }
   return Object::null();
 }
 
 
 DEFINE_NATIVE_ENTRY(VMService_SendObjectRootServiceMessage, 1) {
   GET_NON_NULL_NATIVE_ARGUMENT(Array, message, arguments->NativeArgAt(0));
   if (FLAG_support_service) {
-    Service::HandleObjectRootMessage(message);
+    return Service::HandleObjectRootMessage(message);
   }
   return Object::null();
 }
 
 
 DEFINE_NATIVE_ENTRY(VMService_OnStart, 0) {
   if (FLAG_trace_service) {
     OS::Print("vm-service: Booting dart:vmservice library.\n");
   }
   // Boot the dart:vmservice library.
@@ skipping 334 matching lines @@
     ServiceEvent spawn_event(NULL, ServiceEvent::kIsolateSpawn);
     spawn_event.set_spawn_token(&token);
     spawn_event.set_spawn_error(&String::Cast(result));
     Service::HandleEvent(&spawn_event);
   }
 #endif  // PRODUCT
   return Object::null();
 }
 
 }  // namespace dart