Move StartIsolateScope into MessageHandler::HandleMessages

runtime/vm/isolate.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 "vm/isolate.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/json.h"
 #include "vm/code_observers.h"
@@ skipping 254 matching lines @@
   }
   Dart_MessageNotifyCallback callback = I->message_notify_callback();
   if (callback) {
     // Allow the embedder to handle message notification.
     (*callback)(Api::CastIsolate(I));
   }
 }
 
 
 bool IsolateMessageHandler::HandleMessage(Message* message) {
-  StartIsolateScope start_scope(I);
   StackZone zone(I);
   HandleScope handle_scope(I);
   // TODO(turnidge): Rework collection total dart execution.  This can
   // overcount when other things (gc, compilation) are active.
   TIMERSCOPE(isolate_, time_dart_execution);
 
   // If the message is in band we lookup the handler to dispatch to.  If the
   // receive port was closed, we drop the message without deserializing it.
   // Illegal port is a special case for artificially enqueued isolate library
   // messages which are handled in C++ code below.
@@ skipping 1345 matching lines @@
                            serialized_message_, serialized_message_len_);
 }
 
 
 void IsolateSpawnState::Cleanup() {
   SwitchIsolateScope switch_scope(I);
   Dart::ShutdownIsolate();
 }
 
 }  // namespace dart