Re-duplicate frontend_accessors.dart.

pkg/front_end/lib/src/fasta/kernel/fasta_accessors.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.fasta_accessors;
 
-export 'package:kernel/frontend/accessors.dart' show wrapInvalid;
+export 'frontend_accessors.dart' show wrapInvalid;
 
-import 'package:kernel/frontend/accessors.dart'
-    show Accessor, buildIsNull, makeLet;
+import 'frontend_accessors.dart' show Accessor, buildIsNull, makeLet;
 
 import 'package:kernel/ast.dart';
 
 import '../errors.dart' show internalError;
 
 import '../builder/scope.dart' show AccessErrorBuilder, ProblemBuilder;
 
-import 'package:kernel/frontend/accessors.dart' as kernel
+import 'frontend_accessors.dart' as kernel
     show
         IndexAccessor,
         NullAwarePropertyAccessor,
         PropertyAccessor,
         ReadOnlyAccessor,
         StaticAccessor,
         SuperIndexAccessor,
         SuperPropertyAccessor,
         ThisIndexAccessor,
         ThisPropertyAccessor,
@@ skipping 787 matching lines @@
         new ConditionalExpression(
             buildIsNull(new VariableGet(variable)),
             new NullLiteral(),
             new MethodInvocation(new VariableGet(variable), name, arguments)
               ..fileOffset = offset,
             const DynamicType()));
   } else {
     return new MethodInvocation(receiver, name, arguments)..fileOffset = offset;
   }
 }