Compute bounds of type variables.

pkg/front_end/lib/src/fasta/builder/library_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.library_builder;
 
 import '../combinator.dart' show
     Combinator;
 
 import '../errors.dart' show
     InputError;
 
 import '../export.dart' show
     Export;
 
 import '../loader.dart' show
     Loader;
 
 import 'builder.dart' show
     Builder,
+    ClassBuilder,
     InvalidTypeBuilder,
     TypeBuilder;
 
 import 'scope.dart' show
    Scope;
 
 abstract class LibraryBuilder<T extends TypeBuilder, R> extends Builder {
   final List<Export> exporters = <Export>[];
 
   final List<InputError> compileTimeErrors = <InputError>[];
@@ skipping 31 matching lines @@
   }
 
   bool addToExportScope(String name, Builder member);
 
   void addToScope(String name, Builder member);
 
   InvalidTypeBuilder buildAmbiguousBuilder(
       String name, Builder builder, Builder other, int charOffset);
 
   int finishStaticInvocations() => 0;
+
+  int finishTypeVariables(ClassBuilder object) => 0;
 }