fixed bugs in ios version

ios/Flutter/Flutter.framework/Headers/FlutterHeadlessDartRunner.h

@@ -0,0 +1,34 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FLUTTER_FLUTTERHEADLESSDARTRUNNER_H_
+#define FLUTTER_FLUTTERHEADLESSDARTRUNNER_H_
+
+#import <Foundation/Foundation.h>
+
+#include "FlutterDartProject.h"
+#include "FlutterMacros.h"
+
+/**
+ The FlutterHeadlessDartRunner runs Flutter Dart code with a null rasterizer,
+ and no native drawing surface. It is appropriate for use in running Dart
+ code e.g. in the background from a plugin.
+*/
+FLUTTER_EXPORT
+@interface FlutterHeadlessDartRunner : NSObject
+
+/**
+ Runs a Dart function on an Isolate that is not the main application's Isolate.
+ The first call will create a new Isolate. Subsequent calls will reuse that
+ Isolate. The Isolate is destroyed when the FlutterHeadlessDartRunner is
+ destroyed.
+
+ - Parameter entrypoint: The name of a top-level function from the same Dart
+   library that contains the app's main() function.
+*/
+- (void)runWithEntrypoint:(NSString*)entrypoint;
+
+@end
+
+#endif  // FLUTTER_FLUTTERHEADLESSDARTRUNNER_H_