Handle type variables.

pkg/front_end/lib/src/fasta/builder/type_builder.dart

Index: pkg/front_end/lib/src/fasta/builder/type_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/builder/type_builder.dart b/pkg/front_end/lib/src/fasta/builder/type_builder.dart
index 850bb43a780a25df4a6d7c410b167088638d6095..9f6516f905925df551651d6b554ad421a5bf0b9d 100644
--- a/pkg/front_end/lib/src/fasta/builder/type_builder.dart
+++ b/pkg/front_end/lib/src/fasta/builder/type_builder.dart
@@ -6,6 +6,7 @@ library fasta.type_builder;
 
 import 'builder.dart' show
     Builder,
+    TypeDeclarationBuilder,
     TypeVariableBuilder;
 
 import 'scope.dart' show
@@ -15,6 +16,11 @@ import 'scope.dart' show
 abstract class TypeBuilder extends Builder {
   void resolveIn(Scope scope);
 
+  void bind(TypeDeclarationBuilder builder);
+
+  /// May return null, for example, for mixin applications.
+  String get name;
+
   String get debugName;
 
   StringBuffer printOn(StringBuffer buffer);