Use entities in main_call_stub_generator

pkg/compiler/lib/src/js_backend/backend_helpers.dart

 // 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.
 
 library dart2js.js_backend.helpers;
 
 import '../common.dart';
 import '../common/names.dart' show Identifiers, Uris;
 import '../common/resolution.dart' show Resolution;
 import '../compiler.dart' show Compiler;
@@ skipping 801 matching lines @@
   }
 
   MethodElement get functionTypeTestMetaHelper {
     return _findHelper('functionTypeTestMetaHelper');
   }
 
   MethodElement get defineProperty {
     return _findHelper('defineProperty');
   }
 
-  Element get startRootIsolate {
+  MethodElement get startRootIsolate {
     return _find(isolateHelperLibrary, START_ROOT_ISOLATE);
   }
 
   Element get currentIsolate {
     return _find(isolateHelperLibrary, '_currentIsolate');
   }
 
   Element get callInIsolate {
     return _find(isolateHelperLibrary, '_callInIsolate');
   }
@@ skipping 42 matching lines @@
   }
 
   MethodElement get toStringForNativeObject {
     return _findHelper('toStringForNativeObject');
   }
 
   MethodElement get hashCodeForNativeObject {
     return _findHelper('hashCodeForNativeObject');
   }
 }