Add KernelCodegenWorkItem stub

pkg/compiler/lib/src/js_backend/codegen_listener.dart

Index: pkg/compiler/lib/src/js_backend/codegen_listener.dart
diff --git a/pkg/compiler/lib/src/js_backend/codegen_listener.dart b/pkg/compiler/lib/src/js_backend/codegen_listener.dart
index f62d9d2e283b2789221d374643e464b5ec80bb12..1eda02e5cf8c672d9fde4d46a2963db9d4845cc0 100644
--- a/pkg/compiler/lib/src/js_backend/codegen_listener.dart
+++ b/pkg/compiler/lib/src/js_backend/codegen_listener.dart
@@ -243,16 +243,15 @@ class CodegenEnqueuerListener extends EnqueuerListener {
   }
 
   @override
-  WorldImpact registerUsedElement(MemberElement member) {
+  WorldImpact registerUsedElement(MemberEntity member) {
     WorldImpactBuilderImpl worldImpact = new WorldImpactBuilderImpl();
     _customElementsAnalysis.registerStaticUse(member);
 
     if (member.isFunction && member.isInstanceMember) {
-      MethodElement method = member;
-      ClassElement cls = method.enclosingClass;
-      if (method.name == Identifiers.call &&
-          !cls.typeVariables.isEmpty &&
-          _rtiNeed.methodNeedsRti(method)) {
+      ClassEntity cls = member.enclosingClass;
+      if (member.name == Identifiers.call &&
+          _elementEnvironment.isGenericClass(cls) &&
+          _rtiNeed.methodNeedsRti(member)) {
         worldImpact.addImpact(_registerComputeSignature());
       }
     }