Some more refactorings of overload dispatcher generation.

sdk/lib/indexed_db/dartium/indexed_db_dartium.dart

 library indexed_db;
 
 import 'dart:async';
 import 'dart:html';
 import 'dart:html_common';
 import 'dart:nativewrappers';
 // Copyright (c) 2012, 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.
 
@@ skipping 53 matching lines @@
   @DomName('IDBCursor.advance')
   @DocsEditable
   void advance(int count) native "IDBCursor_advance_Callback";
 
   void continueFunction([/*IDBKey*/ key]) {
     if (?key) {
       _continue_1(key);
       return;
     }
     _continue_2();
+    return;
   }
 
   @DomName('IDBCursor._continue_1')
   @DocsEditable
   void _continue_1(key) native "IDBCursor__continue_1_Callback";
 
   @DomName('IDBCursor._continue_2')
   @DocsEditable
   void _continue_2() native "IDBCursor__continue_2_Callback";
 
@@ skipping 971 matching lines @@
 
 // WARNING: Do not edit - generated code.
 
 
 @DocsEditable
 @DomName('IDBAny')
 class _Any extends NativeFieldWrapperClass1 {
   _Any.internal();
 
 }