Add ElementCodegenWorldBuilder

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

Index: pkg/compiler/lib/src/js_emitter/type_test_registry.dart
diff --git a/pkg/compiler/lib/src/js_emitter/type_test_registry.dart b/pkg/compiler/lib/src/js_emitter/type_test_registry.dart
index 2df546a49bc23eb36f3ee27ddd0a282af50af692..b6dc0d0ed70a5c3239274c20041ede5ce26c8ade 100644
--- a/pkg/compiler/lib/src/js_emitter/type_test_registry.dart
+++ b/pkg/compiler/lib/src/js_emitter/type_test_registry.dart
@@ -7,7 +7,7 @@ library dart2js.js_emitter.type_test_registry;
 import '../common.dart';
 import '../common_elements.dart';
 import '../elements/elements.dart'
-    show ClassElement, Element, ElementKind, MemberElement, MethodElement;
+    show ClassElement, ElementKind, MemberElement, MethodElement;
 import '../elements/entities.dart';
 import '../elements/resolution_types.dart'
     show
@@ -138,7 +138,7 @@ class TypeTestRegistry {
       }
     }
 
-    bool canTearOff(Element function) {
+    bool canTearOff(MemberElement function) {
       if (!function.isFunction ||
           function.isConstructor ||
           function.isAccessor) {