Fix file descriptor leak in event handler implementation. When shutting down an isolate, we did not…

runtime/bin/eventhandler.h

Index: runtime/bin/eventhandler.h
diff --git a/runtime/bin/eventhandler.h b/runtime/bin/eventhandler.h
index 530cc8f8d144216cbf9a38879c5e6ce9a060bc54..c487c52ba0cb8df92c0b5db98e28156b5c9ddb35 100644
--- a/runtime/bin/eventhandler.h
+++ b/runtime/bin/eventhandler.h
@@ -50,7 +50,7 @@ class EventHandler {
 
   static EventHandler* Start() {
     EventHandler* handler = new EventHandler();
-    handler->delegate_.Start();
+    handler->delegate_.Start(handler);
     IsolateData* isolate_data =
         reinterpret_cast<IsolateData*>(Dart_CurrentIsolateData());
     isolate_data->event_handler = handler;
@@ -58,6 +58,7 @@ class EventHandler {
   }
 
  private:
+  friend class EventHandlerImplementation;
   EventHandlerImplementation delegate_;
 };