Rewrite mixin application handling in Fasta.

pkg/front_end/lib/src/fasta/source/outline_builder.dart

 // Copyright (c) 2016, 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 fasta.outline_builder;
 
 import 'package:kernel/ast.dart' show AsyncMarker, ProcedureKind;
 
 import '../fasta_codes.dart' show FastaMessage, codeExpectedBlockToSkip;
 
@@ skipping 423 matching lines @@
 
   @override
   void endNamedMixinApplication(Token beginToken, Token classKeyword,
       Token equals, Token implementsKeyword, Token endToken) {
     debugEvent("endNamedMixinApplication");
     List<TypeBuilder> interfaces = popIfNotNull(implementsKeyword);
     TypeBuilder mixinApplication = pop();
     List<TypeVariableBuilder> typeVariables = pop();
     int charOffset = pop();
     String name = pop();
-    if (typeVariables != null && mixinApplication is MixinApplicationBuilder) {
-      mixinApplication.typeVariables = typeVariables;
-      mixinApplication.subclassName = name;
-    }
     int modifiers = Modifier.validate(pop());
     List<MetadataBuilder> metadata = pop();
     library.addNamedMixinApplication(metadata, name, typeVariables, modifiers,
         mixinApplication, interfaces, charOffset);
     checkEmpty(beginToken.charOffset);
   }
 
   @override
   void endTypeArguments(int count, Token beginToken, Token endToken) {
     debugEvent("TypeArguments");
@@ skipping 397 matching lines @@
   Link<Token> handleMemberName(Link<Token> identifiers) {
     if (!isDartLibrary || identifiers.isEmpty) return identifiers;
     return removeNativeClause(identifiers);
   }
 
   @override
   void debugEvent(String name) {
     // printEvent(name);
   }
 }