Extract invoke-main stub generator.

pkg/compiler/lib/src/js_emitter/model.dart

 // Copyright (c) 2014, 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.new_js_emitter.model;
 
-import '../js/js.dart' as js show Expression;
+import '../js/js.dart' as js show Expression, Statement;
 import '../constants/values.dart' show ConstantValue;
 
 import '../deferred_load.dart' show OutputUnit;
 
 import 'js_emitter.dart' show MetadataCollector;
 
 import '../common.dart';
 
 class Program {
   final List<Fragment> fragments;
@@ skipping 78 matching lines @@
   MainFragment get mainFragment;
 }
 
 /**
  * The main output file.
  *
  * This code emitted from this [Fragment] must be loaded first. It can then load
  * other [DeferredFragment]s.
  */
 class MainFragment extends Fragment {
-  final js.Expression main;
+  final js.Statement invokeMain;
   final List<Holder> holders;
 
   MainFragment(OutputUnit outputUnit,
                String outputFileName,
-               this.main,
+               this.invokeMain,
                List<Library> libraries,
                List<StaticField> staticNonFinalFields,
                List<StaticField> staticLazilyInitializedFields,
                List<Constant> constants,
                this.holders)
       : super(outputUnit,
               outputFileName,
               libraries,
               staticNonFinalFields,
               staticLazilyInitializedFields,
@@ skipping 312 matching lines @@
               tearOffName : tearOffName,
               canBeApplied : canBeApplied,
               canBeReflected : canBeReflected);
 }
 
 class StaticStubMethod extends StubMethod implements StaticMethod {
   Holder holder;
   StaticStubMethod(String name, this.holder, js.Expression code)
       : super(name, code);
 }