Move code that sends an isolate shutdown message to the service isola…

…te to the block after we transition the thread state to ThreadInVM.

R=johnmccutchan@google.com

Review URL: https://codereview.chromium.org/2047123002 .

runtime/vm/dart.cc

@@ -655,7 +655,6 @@ void Dart::RunShutdownCallback() {
   Isolate* isolate = Isolate::Current();
   void* callback_data = isolate->init_callback_data();
   Dart_IsolateShutdownCallback callback = Isolate::ShutdownCallback();
-  ServiceIsolate::SendIsolateShutdownMessage();
   if (callback != NULL) {
     (callback)(callback_data);
   }

runtime/vm/dart_api_impl.cc

@@ -1297,13 +1297,14 @@ DART_EXPORT void Dart_ShutdownIsolate() {
     StackZone zone(T);
     HandleScope handle_scope(T);
     Dart::RunShutdownCallback();
+    // The Thread structure is disassociated from the isolate, we do the
+    // safepoint transition explicity here instead of using the TransitionXXX
+    // scope objects as the original transition happened outside this scope in
+    // Dart_EnterIsolate/Dart_CreateIsolate.
+    T->ExitSafepoint();
+    T->set_execution_state(Thread::kThreadInVM);
+    ServiceIsolate::SendIsolateShutdownMessage();
   }
-  // The Thread structure is disassociated from the isolate, we do the
-  // safepoint transition explicity here instead of using the TransitionXXX
-  // scope objects as the original transition happened outside this scope in
-  // Dart_EnterIsolate/Dart_CreateIsolate.
-  T->ExitSafepoint();
-  T->set_execution_state(Thread::kThreadInVM);
   Dart::ShutdownIsolate();
 }