Make typedefs lazy again

lib/src/codegen/js_codegen.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 dev_compiler.src.codegen.js_codegen;
 
 import 'dart:collection' show HashSet, HashMap;
 
 import 'package:analyzer/analyzer.dart' hide ConstantEvaluator;
 import 'package:analyzer/src/generated/ast.dart' hide ConstantEvaluator;
@@ skipping 264 matching lines @@
     return null;
   }
 
   @override
   visitFunctionTypeAlias(FunctionTypeAlias node) {
     // If we've already emitted this class, skip it.
     var element = node.element;
     var type = element.type;
     var name = element.name;
 
-    _loader.startTopLevel(element);
-    var fnType = js.statement('let # = dart.typedef(#, #);', [
+    var fnType = js.statement('let # = dart.typedef(#, () => #);', [
       name,
       js.string(name, "'"),
       _emitTypeName(type, lowerTypedef: true)
     ]);
-    _loader.finishTopLevel(element);
 
     return _finishClassDef(type, fnType);
   }
 
   @override
   JS.Expression visitTypeName(TypeName node) => _emitTypeName(node.type);
 
   @override
   JS.Statement visitClassTypeAlias(ClassTypeAlias node) {
     // If we've already emitted this class, skip it.
@@ skipping 2175 matching lines @@
 
 /// A special kind of element created by the compiler, signifying a temporary
 /// variable. These objects use instance equality, and should be shared
 /// everywhere in the tree where they are treated as the same variable.
 class TemporaryVariableElement extends LocalVariableElementImpl {
   TemporaryVariableElement.forNode(Identifier name) : super.forNode(name);
 
   int get hashCode => identityHashCode(this);
   bool operator ==(Object other) => identical(this, other);
 }