Implement type variables in mixin applications.

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

Index: pkg/front_end/lib/src/fasta/builder/mixin_application_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/builder/mixin_application_builder.dart b/pkg/front_end/lib/src/fasta/builder/mixin_application_builder.dart
index e7b319693bbe1ea379aa35bdf6dd679f58009781..5e0a052b63b33eb7410663c02eeab525ecc127fa 100644
--- a/pkg/front_end/lib/src/fasta/builder/mixin_application_builder.dart
+++ b/pkg/front_end/lib/src/fasta/builder/mixin_application_builder.dart
@@ -9,7 +9,8 @@ import '../errors.dart' show
 
 import 'builder.dart' show
     TypeBuilder,
-    TypeDeclarationBuilder;
+    TypeDeclarationBuilder,
+    TypeVariableBuilder;
 
 import 'scope.dart' show
     Scope;
@@ -23,6 +24,16 @@ abstract class MixinApplicationBuilder<T extends TypeBuilder>
       Uri fileUri)
       : super(charOffset, fileUri);
 
+  void set typeVariables(List<TypeVariableBuilder> variables);
+
+  /// If this mixin application uses type variables, it needs a unique name
+  /// based on its subclass. If this name is provided, the name will be
+  /// `name^mixin`, otherwise it'll be `superclass&mixin`.
+  //
+  // TODO(ahe): This is to reduce diff against dartk. Consider if this is
+  // necessary.
+  void set subclassName(String value);
+
   String get name => null;
 
   void resolveIn(Scope scope) {