dart2js: fully assemble program before emitting it.

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, Statement;
 import '../constants/values.dart' show ConstantValue;
 
 import '../deferred_load.dart' show OutputUnit;
@@ skipping 53 matching lines @@
   /// Note: the metadata is derived from the task's `metadataCollector`. The
   /// list must not be emitted before all operations on it are done. For
   /// example, the old emitter generates metadata when emitting reflection
   /// data.
   Map<OutputUnit, List<String>> get metadataTypes
       => _metadataCollector.types;
 
 
   bool get isSplit => fragments.length > 1;
   Iterable<Fragment> get deferredFragments => fragments.skip(1);
+  Fragment get mainFragment => fragments.first;
 }
 
 /**
  * This class represents a JavaScript object that contains static state, like
  * classes or functions.
  */
 class Holder {
   final String name;
   final int index;
   Holder(this.name, this.index);
@@ skipping 396 matching lines @@
               requiredParameterCount: requiredParameterCount,
               optionalParameterDefaultValues: optionalParameterDefaultValues,
               functionType: functionType);
 }
 
 class StaticStubMethod extends StubMethod implements StaticMethod {
   Holder holder;
   StaticStubMethod(String name, this.holder, js.Expression code)
       : super(name, code);
 }