Remove support for mixin typedefs in dart2js.

pkg/compiler/lib/src/parser/element_listener.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.parser.element_listener;
 
 import '../common.dart';
 import '../diagnostics/messages.dart' show MessageTemplate;
 import '../elements/elements.dart'
     show Element, LibraryElement, MetadataAnnotation;
@@ skipping 255 matching lines @@
     popNode(); // returnType
     pushElement(new PartialTypedefElement(
         name.source, compilationUnitElement, typedefKeyword, endToken));
     rejectBuiltInIdentifier(name);
   }
 
   void endNamedMixinApplication(
       Token classKeyword, Token implementsKeyword, Token endToken) {
     NodeList interfaces = (implementsKeyword != null) ? popNode() : null;
     MixinApplication mixinApplication = popNode();
-    Modifiers modifiers = popNode();
     NodeList typeParameters = popNode();
     Identifier name = popNode();
+    Modifiers modifiers = popNode();
     NamedMixinApplication namedMixinApplication = new NamedMixinApplication(
         name,
         typeParameters,
         modifiers,
         mixinApplication,
         interfaces,
         classKeyword,
         endToken);
 
     int id = idGenerator.getNextFreeId();
@@ skipping 458 matching lines @@
   void reportErrorHelper(Spannable spannable, MessageKind errorCode,
       [Map arguments = const {}]) {
     if (currentMemberHasParseError) return; // Error already reported.
     if (suppressParseErrors) return;
     if (!memberErrors.isEmpty) {
       memberErrors = memberErrors.tail.prepend(true);
     }
     reporter.reportErrorMessage(spannable, errorCode, arguments);
   }
 }