Introduce TypedefEntity

pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart

Index: pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart
diff --git a/pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart b/pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart
index 9b4955b8d101c35410746bfc41ef873b4f69562c..c6b1318177708c9d9b66636281fb4255e85ee77a 100644
--- a/pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart
+++ b/pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart
@@ -17,15 +17,13 @@ import '../../deferred_load.dart' show DeferredLoadTask, OutputUnit;
 import '../../elements/elements.dart'
     show
         ClassElement,
-        Elements,
         FieldElement,
         FunctionSignature,
         GetterElement,
         LibraryElement,
         MemberElement,
         MethodElement,
-        ParameterElement,
-        TypedefElement;
+        ParameterElement;
 import '../../elements/entities.dart';
 import '../../elements/resolution_types.dart'
     show ResolutionDartType, ResolutionFunctionType, ResolutionTypedefType;